All language subtitles for Battle.Of.Britain.The.Race.For.Radar.1080p.WEB.x264.AC3.MVGroup.org

(gulls cawing)

(dramatic music)

- [Narrator] Just a few weeks
before the Second World War,

Germany's huge Graf Zeppelin
crossed the North Sea

on a daring spy mission.

Onboard, a team of military
and wireless experts

spent the next 24 hours
probing the mysterious towers

that had appeared around
the British coastline.

This spy mission had been ordered

by the head of German signals,
General Wolfgang Martini.

(speaking in foreign language)

He knew the war was just weeks away,

and he desperately needed to
find out more about the towers.

Were the zeppelin's spies

about to unravel
Britain's greatest secret?

(dramatic music)

(overlapping speech)

(planes buzzing)

In the summer of 1940, Britain
fought for its very survival

in the skies over southern England.

But the full story has never been told.

Churchill's few had gained
a huge tactical advantage

from the work of a brilliant
team of scientists.

In just four frantic
years, Robert Watson-Watt

led the team that designed
and constructed Chain Home,

the world's first radar defense system.

- There was no plan B.

The entire defense of Britain

was gambled on Watson-Watt
and his boffins.

(overlapping speech)

- The Battle of Britain was,
in fact, won some years before

by the decision to build Chain Home

and to develop the very
effective communication system

between it and Fighter Command.

That's something which
one can't underestimate.

(overlapping speech)

It was the use of the information
that was so important.

- It's exceedingly unlikely

that we would have won the
Battle of Britain in 1940

without the ability to preserve
our Hurricane and Spitfires

and our pilots on the ground

until a real attack was developing.

- [Operator] Beacon hill.

Intercept raid 45.

(bell tinging)

- [Narrator] Radar gave
the Royal Air Force

a crucial 20-minutes early warning.

This enabled Fighter Command to scramble

and direct its fighters to
exactly where they needed to be.

- Beacon Hill.

Will you warn your comptroller

this looks like yet another
attack on air fields.

- [Narrator] As the
world's largest air force

began its assault on Britain,

Luftwaffe commander Hermann Goring boasted

he would seize control of British
skies in a matter of days.

Destroying the RAF was the
prelude to Operation Sea Lion,

the invasion of Britain.

- If air supremacy had
passed to the Germans,

they would have attempted Sea Lion,

and had it done so, it would
probably have been successful.

- [Narrator] The RAF fought
the Battle of Britain

under the assumption that the Germans

knew all the secrets of British radar.

There could be no other reason behind

the zeppelin spy flight in
those last weeks of peace.

- The conclusion we reached

was that they had
located all the stations,

and therefore the most probable thing

would be an attack on them in
the early stage of the war.

- [Narrator] So why had the Germans

not destroyed British
radar before the battle?

The mystery of the zeppelin spy mission

was not solved until long after the war.

(booming)

(artillery blasting)

When the guns finally fell silent in 1918,

the world had been traumatized

by the horrors of modern warfare.

Further conflict in Europe
seemed inconceivable.

- After the immediate end
of the First World War,

there was a widespread
feeling among the public

that they didn't want any more war,

that it would be the end of war.

And so defenses were run down immediately.

The RAF, which had been created in 1918,

became a fraction of itself,

partly because there was no sense

that there was really any enemy out there.

Who was now going to attack Great Britain?

(soft music)

- [Narrator] But things
were about to change.

The defeated Germany was soon
ravaged by hyperinflation,

unemployment, and civil unrest.

From this chaos, a
sinister new force emerged.

Hitler's rise to power
was born of the resentment

of the harsh reparations imposed

at the end of the First World War.

He promised a new and stronger Germany.

(shouting)

- By the time Hitler
came to power in 1933,

they were close to the point
where they could now begin

to build once again a military air force,

and a military air force
with advanced technology.

He made his sidekick, Hermann
Goring, Minister for Air.

- [Narrator] Forbidden to rearm,

the German aircraft industry
had turned to civil aviation.

This became part of Goring's plan

to construct a secret air force.

By the mid-1930s, German
aviation was leading the world.

But these new, high-speed
airliners and mail planes

were barely-disguised bombers.

- This was something I think the British

had always anticipated, but
they soon became terrified

that all the rumors coming back

there were aircraft that
had been seen camouflaged,

about developments of
secret air bases and so on

suggested to them that Germany

was going to be the real threat.

(soft music)

- [Narrator] For centuries, the sea

had been Britain's natural defense.

But a new and terrifying
scenario now loomed.

A new generation of German bombers

could strike targets across the country

before the RAF had time to intercept.

Britain was no longer an island.

It desperately needed
an early warning system.

- [Soldier] Off-style
aircraft coming in northeast.

Fresh target south.

- During the First World War,

sound locators were a successful method

of being able to track aircraft

close in to the British coast.

And during the 1930s,
the British government

decided to build even
larger sound locators

in the hope of detecting aircraft

many miles away from the coast.

- [Narrator] If proven effective,

these concrete sound
locators could be developed

into a national warning system.

With the massive 200-foot
sound mirror just completed,

everything now depended on a crucial test.

- And it was a classic
story of the air staff

all assembled for a demonstration,

listening to the incoming
bomber formation.

It sounded very much as
though one of the planes

has a faulty engine.

- [Soldier] Here's something.

Fresh target south.

- And all they saw was
the local dairy farmer

with his milk cart and his
milk jars rattling together.

And that was the state of
our air defense in 1934.

- [Narrator] Amongst those
who witnessed the fiasco

was the head of Air Ministry
Research, Hugh Dowding,

and one of his scientists, A.P. Rowe.

- Rowe realized that the day
of the sound locator was over.

He wrote to his boss and said that,

unless urgent action was taken,

Britain would lose the next war.

- [Narrator] It had taken a milk float

to rattle the government into action.

- 30 enemy aircraft over the
channel, flying due west.

- [Narrator] The RAF had
neither the men or aircraft

to maintain a constant patrol

over the entire eastern seaboard.

- German bombers could
attack across the North Sea

anywhere from the Orkneys
down to the Isle of Wight,

a vast area of 70,000 square miles.

- [Narrator] If an early warning
system could be developed

with a range of 100
miles, then RAF fighters

could remain on the ground
until the enemy was detected.

- In 1935, the idea of a warning system

that would cover 70,000 square miles

was the most utter science fiction.

(dramatic music)

- [Narrator] In the
cinemas, popular serials

were full of fantastic
and futuristic ideas.

Evil empires, robots,
poison gas, and ray guns.

Britain's defense establishment

also got caught up in this
science fiction fever.

(soft music)

Rumors began to circulate that the Germans

were developing a death ray,

a high-energy beam that would
boil the blood of a pilot.

(dramatic music)

- This was taken
seriously by Air Ministry,

and they offered a prize,
an award of 1,000 pounds

for anyone who could kill
a sheep at 200 yards.

(electricity buzzing)

(sheep bleating)

(booming)

- [Narrator] The death ray
challenge found its way

to the obscure radio
research station near Slough.

Its chief scientist was a lively Scot

called Robert Watson-Watt.

- Watson-Watt.

- Watson-Watt was a marvelous little chap.

He babbled away the whole time, talking.

He could certainly charm
a monkey out of a tree,

certainly, without the slightest effort.

- [Narrator] Watson-Watt
asked his able assistant,

Skip Wilkins, to get to grips
with the death ray conundrum.

He soon found the energy required

would be out of this world.

- Hello, can you put me through
to Air Ministry, please.

- [Narrator] But Watson-Watt
sensed an opportunity

with the Air Ministry.

- I'd like to speak to
Dr. Whittingham, please.

- Watson-Watt was a marvelous salesman.

He could sell refrigerators to Eskimos

without the slightest effort.

- Harold! (chuckling)

- Watson-Watt replied, saying,
"Absolutely impossible,

"but I believe I can use radio energy

"to detect an enemy bomber."

- Okay, buh-bye.

Buh-bye.

(thunder clapping)

- [Narrator] But this extravagant claim

was based on little more than a hunch.

Watson-Watt had been
tracking thunderstorms

by radio direction finding,

when he became puzzled by
some mysterious reflections.

Wilkins suggested they might be echoes

from passing aircraft.

So when the Air Ministry
demanded he prove his claim,

he turned again to his young assistant.

Wilkins estimated how much radio energy

could be reflected from an aircraft.

The answer surprised everyone.

It was very favorable.

- Air Marshal Dowding,
the head of Air Ministry

research and development, saw
the calculations but said,

"These scientific fellows can
prove anything with figures.

"I want a demonstration."

- [Narrator] Within a few days,

Wilkins devised a pioneering experiment.

- [Watson-Watt] Permission
to come aboard, Mr. Wilkins.

- [Wilkins] Welcome, come on it.

- [Narrator] The mobile
laboratory was an old ambulance,

packed with hastily improvised equipment.

A Heyford bomber would fly a course

between the BBC transmitter
at Daventry and the van.

Any radio reflections from the aircraft

would disturb the display.

A.P. Rowe from the Air
Ministry joined them

as they anxiously awaited the bomber.

- Do you hear that?

Some sort of hum.

It's definitely an engine.

It could be our man.

- [Narrator] As the
engine drone grew louder,

the spot refused to move.

- It could be atmospheric skip.

- [Narrator] The Heyford turned
and made a second approach.

- It could be a tractor.

- No, no, no, no.

That's some ...

That is our man! (laughing)

Contact!

There he goes! (laughs)

- [Narrator] Wilkins had made
Britain's first radar contact,

and Watson-Watt was quick
to realize the significance.

- Well, Skip, Mr. Rowe,

Britain is now in the game. (laughs)

- [Narrator] With deep
irony, Wilkins' success

came on the very same day that Hitler

revealed the Luftwaffe to the world.

It was the first exhibition
of military might

by the self-appointed fuhrer.

In just two years, the
Nazis had constructed

the world's largest air
force in total secrecy.

Hitler's old henchman, Hermann Goring,

was given supreme command.

The threat to Britain
was now all too clear.

(planes buzzing)

Following that first radar experiment,

Air Marshal Dowding took decisive action.

10,000 pounds of funding
allowed Watson-Watt

to gather a small team of scientists

at a remote aerodrome in Suffolk.

- The conditions in
the actual laboratories

where we worked on radar
were completely primitive.

They were just wooden huts.

All our test gear had
come over on the boat,

everything came over on the boat,

and there simply wasn't
much test gear anyhow.

- [Narrator] As the
team explored the design

of a national early warning system,

some of the more fanciful
ideas began to raise alarm.

- Watson-Watt, in addition to being

a good theoretical scientist,
was also a practical champ,

and he was not carried away by
what they could eventually do

as being the most wonderful thing.

He would give people what
was available at the time.

He knew that the RAF
needed something quickly,

and he provided them with something.

And if he gave them the third
best, that was good enough.

- [Narrator] Watson-Watt
knew the frantic race

to defend Britain could only be won

by developing existing technology.

But keeping it simple came with drawbacks.

- The problem was that, to
transmit enough radio power

with existing technology
required the aerials

to be over 300 feet high.

- [Narrator] A national
network would require

dozens of these huge towers
to be linked together

to form a coastal chain.

- The echoes of any aircraft
within that transmission area

were picked up by a receiving system

which could tell the direction

from which the echo was coming.

- [Narrator] Watson-Watt's
third-best system

became known as Chain Home.

- Hello.

Can you put me through to
the Air Ministry, please?

- [Narrator] Many still considered

Watson-Watt's ideas total fantasy.

But he was gaining rapid progress.

- 80,000 pounds would o a long way.

- By July of 1935,
Watson-Watt and his team

were successfully detecting
aeroplanes out of 50, 60 miles.

- [Narrator] The radar team had cracked

the basic mechanics of radar.

It now had to evolve into
an air defense system.

- It was not developed
as a scientific device.

It was developed as a war weapon

for the use of Fighter
Command and the requirements

of Fighter Command were
of overriding priority.

- [Narrator] The expanding research team

had outgrown the primitive
huts Orford Ness.

Just down the coast, the
imposing Bawdsey Manor

became the perfect home for Watson-Watt's

new wave of recruits.

The drive was on to
collect the best brains

from Britain's universities.

- The impact of Bawdsey
Manor and all the equipment

on me as a young man in
my mid-20s was colossal.

- [Narrator] As Bawdsey's
scientific elite grew,

they gained a name that would
stick with them: the boffins.

- We all felt the war was coming,

that we only had a little
time in which to be ready

to defend this country, and
that was the atmosphere.

(dramatic music)

- [Narrator] That year, Things to Come

gave cinema audiences a
terrifying specter of modern war.

(artillery blasting)

(booming)

- One of the key
features, really, I think,

of British society in the
1930s was fear of bombing.

We were told all the time,

taught by Stanley
Baldwin, the Prime Mister,

"The bomber will always get through."

That contributed to this
strong apocalyptic fear

that somehow or other the bomb

represented the end of civilization.

(dramatic music)

(propellor buzzing)

- [Narrator] A year later,
that fear became real.

- The public saw the Germans in Spain

and the bombing of Guernica,
which became high-profile.

- [Narrator] The weekly news reels

left the public recoiling in horror.

(bombs whistling)

- Played a very important part in building

a strong resistance to the idea

of waiting out the war again.

- [Narrator] The Spanish Civil War

proved the perfect testing
ground for the destructive power

of the Luftwaffe's men and machines.

(bombs exploding)

But it was not just in military aviation

that Germany led the world.

The Hindenburg was the latest

of Count von Zeppelin great airships.

The 800-foot leviathan was
a potent propaganda tool,

a symbol of a renewed Germany.

That all changed on the evening
of the 6th of May, 1937.

(flames whooshing)

(dramatic music)

The disaster at Lakehurst spelled the end

of passenger-carrying airships.

But still under
construction was the LZ130,

the new Graf Zeppelin.

Once complete, it
languished in its hangar,

an enormous white elephant.

As the first of the giant 350-foot towers

went up at Bawdsey,
Watson-Watt's confidence grew.

He summoned the top mandarins of Whitehall

for a full-scale demonstration.

- Well, the great day dawned.

And this great fleet of aircraft

left the dock at Phoenixville,

and then they were going to
make an attack on Bawdsey.

Watson-Watt tells how marvelous radar was

and what a great replacement
it would be for sound location.

And the time came, of course,
for these aircraft to appear,

and nothing much was seen
by the three observers.

I was one of the observers.

It became increasingly embarrassing,

and then, finally,
Watson-Watt gave up talking,

because nothing was
appearing on the tube at all,

and of course he could see
no explanation for that,

nor could he think of
any explanation for it.

And in the quiet after he stopped talking,

we began to hear the distant
hum of aircraft engines.

And at the same time as we heard them,

or possibly one second before,
we saw some faint echoes

on the cathode ray tubes.

(plane buzzing)

As a demonstration of
the efficacy of radar,

it was about as bad as
it could possibly get.

- [Narrator] The top brass
stormed back to London,

convinced that Watson-Watt was
little more than a charlatan.

Radar was all but finished.

(dramatic music)

The disaster left only one senior figure

still with confidence in the boffins.

Air Marshall Hugh Dowding understood

the huge technical challenges they faced.

- I'm quite sure Dowding
could see no other solution

to the effective defense of this country.

Use of standing patrols and other means

of detecting and
directing fighter aircraft

against incoming bomber
streams was clearly

well beyond the capability of
the resources of the country.

Radar had to be successful,

and Dowding kept on supporting
it right up to the hilt.

- [Narrator] Dowding was never afraid

to push the boffins to their limits.

- And I recall a meeting at
Fighter Command which I was at,

when he was having a great deal of trouble

with the stability of the CH system.

At this meeting he was thumping the table,

demanding why he couldn't
have a stable system.

And the senior scientist
there, Harold Lander,

said, "Well, sir, the scientists
say it's not possible."

And I remember him beating
the table and saying,

"If the scientists say it's not possible,

"get me another set of scientists."

- Dowding, who was an
absolutely dedicated individual

who drove forward the idea of making radar

the backbone of Britain's fighter defense.

- Radar gave Fighter Command

a method of locating the attacking bomber.

But that was only half the problem.

The other half was to direct the fighter

effectively to intercept.

- [Narrator] Dowding's new
system would keep fighters

on the ground until the
enemy was detected by radar.

- All fighter squadrons take off!

(soft music)

- D11, ring commander speaking.

- Take off at once and patrol your area.

- Right.

There's a radar on the way.

Now, report by radio as
soon as you're on patrol.

That's all.

Good luck.

- [Narrator] Once in the
air, a constant stream

of instructions by two-way radio

would guide them to intercept.

- Orbit, angels 15 and
transmit for fix, over.

- [Pilot] Okay, listening out.

- [Narrator] Scramble, bandits, and angels

became the new language
of fighter command.

- [Operator] Vector 350, over.

- [Pilot] Vector 350.

- Hello, Hazel 22.

Far as answering, damn good show.

- As the development of radar progressed.

Watson-Watt knew that his first priority

was the defense of London.

(anxious music)

- [Narrator] London was less
than 90 minutes' flying time

from major Luftwaffe bomber bases.

At the start of 1938, five radar stations

began construction around
the Thames estuary.

The new radar network was going to need

hundreds of trained personnel.

Foreseeing a lack of manpower in wartime,

the RAF began to recruit women operators.

- Nobody could be told
what they were doing.

It was absolutely Britain's top secret.

- We marched up and
down, we saluted people.

And so it went on for two weeks.

And then, we were all called into a hut

and told where we going to be sent.

And I was told I was going
to be a clark special duty,

and everybody wanted to know what it was.

I couldn't tell them, I had no idea.

And we had our first lecture

when they told us the secret of radar.

- When you were operating on the set,

you had what was called a trace,

which is a line of light across the screen

full of little things wiggling
up and down like that.

And these were either noise
interference or the real thing,

what you were looking for, the
echoes coming off aircraft.

- [Narrator] By spring
of 1938, the five Thames

radar stations gave London
a 20-minute warning.

- Yes, there is a major raid
developing to the southeast.

(alarm sounding)

- [Narrator] But air exercises

were revealing a daunting problem.

20 minutes was proving too little time

for the RAF's biplanes to climb to height.

The air defense of London
would require a new generation

of high-speed monoplane interceptors.

But the complex Spitfire airframe

was proving difficult to
put into mass production.

And the Hawker factory could
not yet give full priority

to the construction of the Hurricane.

By March 1938, just 16
had reached the frontline.

(shouting)

A few weeks later, the
Reichstag rose to the news

that Austria was to unite with Germany.

(anxious music)

The new Graf Zeppelin made a
triumphant flight over Vienna.

It was no longer a white elephant

but a potent symbol of Nazi power.

The flight was cover for
a top secret spy mission.

The Graf headed east to shadow
the Czechoslovakian border.

On board, a team of military
and wireless experts

gathered intelligence on the Sudetenland.

It was Hitler's latest territorial claim,

and it brought Europe to the brink of war.

As the Czech crisis deepened,

Prime Minister Neville
Chamberlain flew to Munich

to confront Hitler head on.

(shouting)

- The problem for Chamberlain
when he arrives in Munich

is that they were close to declaring war

in defense of the Czechs.

But he knew perfectly will that rearmament

was still in immature state.

It had been going on now for
three or four years in Britain,

but the plan was really
to have it completed

by 1939-40 at the very earliest.

- [Narrator] Chamberlain
had just been briefed

on Britain's readiness for war.

- I don't know how strong
Chamberlain's poker face

actually was, but at the time of Munich,

Britain's air defenses can
best be described as dire.

- [Narrator] Munich became
a deadly game of bluff.

- Chamberlain was aware that we had

just 406 fighter aircraft.

Of those, only 70 were Hurricanes,

and just 14 were Spitfires,
not even operational.

(propellor buzzing)

All the rest were obsolete biplanes.

(planes buzzing)

Air raids on London,
Chamberlain had been told,

would result in hundreds
of thousands dead.

Provoking Hitler risked creating
that enormous catastrophe.

- And as Chamberlain
flew back from Munich,

his plane was plotted by the
five coastal CH stations,

passed to the filter room,

and passed up to the operations
room of Fighter Command.

- [Narrator] Mollifying Hitler
had bought a fragile peace.

But Chamberlain's peace for our time

hid a secret race to
complete Britain's defenses.

A new Hawker factory was
now producing Hurricanes

in significant numbers.

And the problems that had
dogged the mass production

of the Spitfire were finally solved.

By the summer of 1939,
five frontline squadrons

had the RAF's fastest fighter.

(dramatic music)

With the frantic construction
of 14 new stations,

radar coverage was extended from Newcastle

to the Isle of Wight.

- The year after Munich was critical.

During that year, the Chain Home system

came into full operation.

- [Narrator] It had taken just four years

from that first experiment
to put Chain Home

at the cornerstone of Britain's defense.

- This led us to ask ourselves a question,

the Germans must know what we're doing.

We're building these stations
and all this activity

going on, 364 steel towers,
240-foot receiving towers.

They can't have missed it.

- [Narrator] One German had
been watching the towers.

General Wolfgang Martini was
the head of German radar.

The latest reconnaissance alarmed him.

Could the mysterious
towers be British radar?

- Martini knew that war
was only weeks away.

He desperately needed to
know more about the towers.

- And on the 3rd of August, 1939,

the radar station just north
of the Thames at Canewden

spotted an echo moving in
towards the Thames estuary,

a massive echo, bigger that anything

one had ever seen before,
moving at some 60, 70 knots.

- [Narrator] Fighter Command
went into high alert.

Could it be an invasion fleet,

or a huge formation of circling bombers?

(ominous music)

- It turned out to be
the German airship LZ130,

the Graf Zeppelin.

And over some hours, they
plotted the movement of the echo

from somewhere of the coast of Essex

up to the north of Scotland.

- [Narrator] Onboard were the
Luftwaffe's top wireless team,

just returned from a spy
mission on the Polish border.

Martini's experts spent the next 24 hours

coming the wavelengths for
any evidence of British radar.

(speaking in foreign language)

- Fighter Command was in complete shock.

The appearance of the zeppelin
could only mean one thing.

- The conclusion we reached

was that they had not only
located all the station;

they would have measured their frequency

and other important characteristics.

And therefore, the most
probable thing would be

an attack on them in the
early stage of the war.

And indeed, we thought that Bawdsey

would be the prime target.

(plane buzzing)

- [Narrator] As the German
war machine rolled into Poland

on the 1st of September, 1939,

Watson-Watt decided the risk
of attack was too great.

Bawdsey must be evacuated.

A.P. Rowe was now the
superintendent of radar research.

He ordered the entire
Bawdsey scientific team

to the safety of Scotland
by any means possible.

Rowe not only feared air
attack on the radar stations

but the electronic jamming of
the entire Chain Home system.

- On September 2nd, Rowe
summoned me and told me,

"Everybody will be going
to Dundee, but not you.

"You will stay and
modify the whole chain."

(crackling)

- [Narrator] Jimmy Atkinson had developed

a new type of display tube that
filtered out enemy jamming.

Every radar station in the country

would need urgent modification.

- I said, "Well, what about transport?"

And Rowe said, "Just do the best you can.

"Use your initiative."

(energetic music)

- [Narrator] Jimmy's ancient
Austin became the latest

secret weapon in the defense of the realm.

He recruited his wife, Mona,
to help with the driving.

- [Jimmy] Now, I was paid subsistence.

But of course, she didn't exist,

even though she had to
do most of the driving,

and I slept during the day,

ready to work at the
next station at night.

- [Narrator] Each station
was taken off the air

while Jimmy fitted the top secret device.

- In September, we covered
a total of 2,648 miles.

- [Narrator] The adventure
was only complete

when the intrepid couple had
toured all 18 radar stations.

In Dundee, the boffins found a home

in the austere teacher training college.

The magic of Bawdsey
Manor had gone for ever.

(anxious music)

- [Operator] Attention, everybody.

It's just been announced
by the Prime Minister

we are at war with Germany.

From now on, anything may happen.

- [Narrator] As war was
declared, Fighter Command

braced itself for a German
onslaught on the radar chain.

- But it didn't happen, and
we couldn't understand why.

- [Narrator] The nation dug
in and prepared for the worst.

But the feared air raids on
British cities never came.

(train whistling)

In April 1940, the phony
war came to a dramatic end.

(dramatic music)

The German Blitzkrieg rampaged
through Holland and Belgium.

(buzzing and rumbling)

A large British expeditionary force

was supporting the defense of France.

But the fast-moving panzers
encircled and trapped them

on the beaches of Dunkirk.

Over 300,000 troops
were snatched to safety

by the royal navy and a
flotilla of small boats.

(booming)

It was a miraculous escape.

Amongst the vast amounts
of material abandoned

in the maelstrom was some
secret radar equipment.

- The British radar sets
which had been captured

were very crude mobile models.

And the Germans concluded that
whatever British radar was,

it certainly wasn't up to much.

(speaking in foreign language)

- [Narrator] The boffins had little idea

of the German intelligence
picture of British radar.

But with the zeppelin
mission and the capture

of the equipment at Dunkirk,
they feared the worst.

The fall of France had
taken just six weeks.

Hitler now turned to Operation Sea Lion,

the invasion of Britain.

- One of the factors that played a role

in persuading Hitler of Operation Sea Lion

was a possibility this was Hermann Goring

really wanted to prove
that his force could do it,

that his force could win
air supremacy over Britain.

And I think people say
that Goring is a fantacist,

he's a boaster, but
actually he had annihilated

the Polish air force in a matter of days.

They defeated all the
aircraft flows at them

in the Battle of France
with relative ease.

The idea that you couldn't
use the same tactics

and destroy the RAF, in
four days Goring thought,

is not as implausible as it now looks.

(dramatic music)

- [Narrator] With the towers
of Dover radar station

clearly visible across the channel,

the Luftwaffe began an attack
on British ports and shipping.

(anxious music)

(plane buzzing)

At first, the Kanalkampf
seemed to go the Germans' way.

Then, the RAF began to appear.

Dowding carefully positioned his fighters

for the best advantage.

- The Germans began began to think,

why are we always meeting the RAF?

We don't think it's very big,
and yet here they always are.

It began to ring rather quiet alarm bells

in the German air force
about whether the British

actually had got some kind of system

to detect incoming aircraft.

- [Narrator] Martini took his fears

directly to Luftwaffe high command.

But Goring was an old-school thinker.

- Hermann Goring was a successful

First World War fighter pilot.

For him, the offensive
spirit of the Luftwaffe

would be the deciding factor,

nothing at all to do with gadgetry.

- [Narrator] If Goring could draw the RAF

into a decisive battle with
his Messerschmitt aces,

then the Spitfire and Hurricane
would be wiped from the sky.

But the events of the 11th of August

were to shatter this confidence.

The Luftwaffe mounted three
widely separated raids

across southern England.

But Dowding had seen the buildup

and had swarms of RAF
fighters ready to intercept.

In just a few hours, the Luftwaffe lost

over 45 aircraft, damaged or destroyed.

(plane buzzing)

But Martini had been monitoring
RAF radio communications.

His suspicions were beginning to grow.

- From intercepts, they
were able to identify

that fighters were being directed

by radio towards the German bombers.

Therefore, radar must be the basis

of the British air defense system.

(speaking in foreign language)

- [Narrator] Martini was also puzzled

by the powerful signals they
could detect from the towers.

They were crude, but somehow
they must play a part

in guiding British fighters.

Goring finally conceded: the
towers must be destroyed.

(dramatic music)

(rumbling)

Early on the 12th of August,

a crack ground attack
squadron crossed the channel.

The frontline radar stations
of Dover, Rye, Pevensey,

and Dunkirk came under direct attack.

(booming)

At Ventnor on the Isle of Wight,

a direct hit caused major damage.

(bombs exploding)

in the following days,
stukas joined the onslaught.

19-year-old Avis Parsons

was on duty at Poling, near Chichester.

- And as a stuka dives, it
screams the most hideous noise.

It's very, very frightening.

And then the bombs began to fall.

(bombs exploding)

I kept going as long as I could,

and suddenly my line went dead.

And the building next to where I was

was just a heap of rubble.

- [Narrator] The attacks on Chain Home

had been feared since
the zeppelin spy mission.

But after three days,
they mysteriously stopped.

- This remained a very great puzzle,

because we knew the extent
of the damage they'd done,

and we knew what they
had to do to finish it,

but they didn't.

- [Narrator] The returning airmen

reported extensive damage to the towers.

But when Martini's experts
checked their frequencies,

they were astonished by what they found.

- The radar signals were still there,

a little fainter, all on
different wavelengths.

Unknown to the Germans,
the source of the signals

were mobile radar vehicles
that had been brought

into operation when
the main radar stations

had been knocked out by the bombing raids.

- [Narrator] Despite the
extensive destruction,

the mobile stations had kept
the radar chain on the air.

The damage to the towers
was rapidly repaired.

- We had all those four
stations back in operation

by midnight that night,
plotting to Fighter Command.

- [Narrator] Quite unintentionally,

the mobile reserve had
been a perfect deception.

With the radar stations
appearing undamaged,

Martini's ideas were sidelined.

Beppo Schmid, the head of
Luftwaffe intelligence,

also had a strong view on
the British radio towers.

- Major Beppo Schmid was a
longstanding Nazi Party member

and a drinking buddy of Hermann Goring.

He has never been accused of
being an intellectual genius.

And he considered that
the tall radio masts

were nothing other than
radio direction finding,

as used in the First World War.

- Goring called a conference
on the 15th of August

and instructed his Luftwaffe commanders

to waste no more time
on these radio stations;

get on and fight the war.

- [Narrator] Goring's
frustrations were growing.

He now had a plan that would call

on every man and aircraft
on the Western front.

- The Chain Home stations began to track

the gathering formations,

extending from 5,000 to 20,000 feet.

- [Operator] Parcel 76,
100 aircraft, 16,000.

(overlapping speech)

- And it was then that we began to get

the very large numbers of aircraft.

It was 100 plus had never been seen

on a radar screen before.

(dramatic music)

- [Narrator] Adlertag or
Eagle Day, was Goring's plan

for a decisive hammer blow.

The target soon became clear.

- [Operator] Will you warn you comptroller

that this looks like yet another
attack on the air fields.

- The thing was to assault the RAF,

its air fields, its bases, depots,

and aircraft production
in southern England.

Once you degraded the
RAF, you then moved on

to attacking communications
and administrative centers,

and then the invasion would take place.

(plane rumbling)

- [Narrator] The RAF air
fields were taking a pounding.

Squadrons were broken up, and fighters

became scattered across southern England.

- There were points in late
August and early September, 1940

where the system was almost
on the point of collapse.

- [Narrator] With Dowding's
ability to deploy his fighters

fast disappearing, the Battle
of Britain was on the brink.

(suspenseful music)

Then came a timely twist of fate.

(dramatic music)

(bombs exploding)

On the night of the 24th
of August, the Luftwaffe

attacked an oil refinery
in the Thames estuary.

But the raid went badly wrong.

Crews got lost, and some
jettisoned their payloads.

For the first time, bombs
fell on central London.

(alarm blaring)

Hitler had forbidden any
attack on the capital,

fearing a reprisal.

He was right.

(propellor buzzing)

Within 24 hours, bomber
command was over Berlin.

(bomb whistling)

(booming)

The token raid did little
damage, but Hitler was outraged.

(shouting in foreign language)

Goring changed his tactics again.

- Beppo Schmid, head of
German air intelligence,

had been telling Goring
over and over again

that the RAF was finished, basically,

just a couple of hundred planes left;

we've achieved air supremacy,

and so it was possible to make this switch

to the bombing of London
without much danger.

(dramatic music)

- [Narrator] Late in the
afternoon of the 7th of September,

the chain stations
plotted large formations

grouping over France.

(operators speaking)

Soon, Hermann Goring had assembled

the largest air armada
the world had ever seen.

370 bombers headed directly
to their target: London.

(booming)

Goring's daily bombardment
continued for weeks.

(bombs exploding)

But shifting his attention
away from the air fields

proved to be a huge tactical error.

- Had the Germans sustained their attacks

on the sector airfields,
and the sector controls

in particular, it would
have been impossible

for Fighter Command to continue
the defense of Britain.

(dramatic music)

- [Narrator] With the
heat off the airfields,

the RAF quickly return to strength.

As Goring continued to pound London,

Dowding used his radar
advantage to the full.

- 100 plus at one-four.

- [Operator] There is a major raid

developing to the southeast.

- [Narrator] He chose
to intercept every raid

with small numbers of fighters

rather than risk all in a pitched battle.

This constant harassment
left German intelligence

only guessing at the strength of the RAF.

- They were told that Fighting Command

was more or less finished.

Every time they flew out, there were more.

- [Narrator] As bomber losses soared,

Goring ordered his fighters
to fly in close escort.

But they lost their advantage of height,

and London was at the
limit of their range.

The Luftwaffe was forced to
seek the cover of darkness.

- The daylight bombing
raids were a disaster,

loss rates that the German air force

simply couldn't support.

And of course, air
supremacy had not been won,

so Sea Lion was abandoned.

(plane buzzing)

- [Narrator] The Battle
of Britain had been won.

(somber music)

But the mystery of the
zeppelin spy mission

was still unresolved.

Why had the Germans not destroyed

British radar before the battle?

The answer only came years
later, after a chance encounter.

It was only after the war, 1950,

I, at the farm air show,
met General Martini,

who was the Chief Signals
Officer of the Luftwaffe.

And I said, "General Martini,
why didn't you destroy

"the radar system when the war broke out?"

He said, "You didn't have a radar system

"when the war broke out."

I said, "Well, how did we
track the Graf Zeppelin?"

He said, "You tracked to Graf Zeppelin?"

"Yes," and I described precisely.

He said, "I don't believe it."

I said, "You have to, we did."

- [Narrator] The astonishing truth dawned.

The zeppelin spies had failed
to identify British radar.

The Luftwaffe's top wireless experts

would have had no trouble finding

the powerful Chain Home signals.

But what they found baffled them.

- They expected to hear
high-pitched noises

and musical tones as you
would get from an oboe

in the middle range of the piano.

(droning tone)

- [Narrator] The latest
German radar equipment

could transmit pulses between
500 and 1,000 times a second.

(clicking)

Nothing like the crude signals
they were now receiving.

- Listening to CH, all you would hear

would be a dull sort
clicking, tick, tick, tick,

something they didn't recognize at all.

(speaking in foreign language)

- German and British radars

were of completely different designs.

German radar generated its own pulses.

British radar, by contrast,

sampled the pulses of the national grid.

- [Narrator] The boffins had
not just used the power cycle

of the national grid as a simple economy;

it was an ingenious way of
synchronizing the entire system.

- All the CH stations all up the coast

were locked together on
their repetition rates.

They all produced 25 pulses per second,

and they were all locked
back to the mains frequency

of 50 cycles per second,

so that they all transmitted in unison.

- [Narrator] To achieve a
100-mile detection range,

Watson-Watt had used the
most powerful transmitters

then available.

Each station produced
more than 600,000 watts.

And because they all derived their pulses

from the national grid,
the entire chain acted

as one enormous and hugely
powerful transmitter.

- So as the airship flew up the coast,

it picked up the same
radiation all the way up,

tick, tick, tick, tick, tick, tick,

ticking, without change.

- [Narrator] This huge wall of radio power

was creating further confusion.

- They had very sensitive receivers

in the main beam of the CH stations,

and they would have
overloaded the receivers

and broken through into other wavebands,

so no matter how they
tuned their receivers,

they would have heard this
curious ticking all the way.

(dramatic music)

- [Narrator] As the LZ130
approached Scotland,

the zeppelin spies still
struggled for an explanation.

The signals appeared to have no direction,

just a general widespread ticking.

With British radar still
blaring from their headphones,

they decided the ticking
could only have one source:

the national grid.

(dramatic music)

- They were completely foxed by the fact

that the repetition
rate of the CH stations,

25 pulses per second,
was quite unlike anything

which they had used on their own radars,

which the Germans mistakenly
took to be arcing and sparking

from the British electrical
distribution system.

(crackling)

- [Narrator] The zeppelin spies had made

the greatest intelligence
blunder of the war.

- The Graf Zeppelin returned,

and the head of the mission reported

that there was no sign of
any radar transmissions.

- Watson-Watt's basic,
almost primitive, system

had spoofed the finest technical
minds in the Luftwaffe.

(laughing)

Ironically, if Watson-Watt
had gone for anything

more sophisticated than third-best,

the Germans would have
been onto it immediately.

- [Narrator] Watson-Watt's great wisdom

had been to keep Chain Home simple.

He knew there could be no delays

in Britain's frantic race for radar.

- It was only just
ready in time as it was.

- [Narrator] The Luftwaffe had botched

the perfect opportunity to
unravel all of the secrets

of Chain Home a year before
the battle of Britain.

- The failure of the zeppelin spy mission

was a fundamental
disaster for the Germans.

They did not realize the
effectiveness of British radar,

nor the substantial size of
the organization behind it,

on which the whole of
British air defense hinged.

- I believe the failure
of the zeppelin mission

and the failure of
Martini to persuade Goring

that the stations had to be destroyed

effectively cost Goring
the Battle of Britain,

and that saved this country
from a German invasion.

(dramatic music)