IF A nuclear bomb was dropped on London tomorrow, where would you go?

It may seem a morbid question, but during the dark days of the Cold War planning for doomsday became a necessity.

A network of bunkers was set up around the country so what was left of it could continue to function after a nuclear attack.

Just outside the village of Duddleswell, near Crowborough, one such shelter still stands.

Packed with untouched Cold War technology, the bunker is now owned by Sussex Police and used to store evidence.

But when it was built in 1942, it served an entirely different purpose: fooling Nazis.

As the Second World War raged on, the Government wanted to broadcast propaganda into Germany to confuse and demoralise its population.

So King’s Standing, as the site was known, was chosen as the location for one of the most powerful transmitters ever made.

In October, American President Franklin Roosevelt sent Prime Minister Winston Churchill a telegram claiming he was “making a radio dish inmediately”.

“While your French grammar is better than mine, my accent is most alluring,” he quipped.

Three 110-metre-tall radio masts were built in America, while in Duddleswell Canadian soldiers set to work digging a 50-foot-deep hole for the bunker.

Known as the Aspidistra, the transmitter was a huge asset for the Allies.

“Britain bought it from them because it surpassed the legal power limit for radio transmitters in the USA,” said Foreign and Commonwealth Office historian Katherine Newton.

In November 1942 the tower became fully operational - and the deception began.

Unlike most transmitters, the Aspidistra could change frequency quickly, which meant it could quickly change channels if the Nazis tried to block its broadcasts.

Fake radio stations were broadcast across Europe to destroy Nazi morale.

In “Operation Dartboard”, fluent German speakers impersonated air traffic control officers and redirected pilots away from Allied bombers.

Under the sea, “Atlantiksender” was aimed at U-Boat crews.

“The aim was to reduce U-Boat crew morale,” said Ms Newton.

“Top-secret missions would be mentioned, or embarrassing gossip.”

As the war changed course and the Allies gained the advantage, use of the Aspidistra became even more nefarious.

During bombing raids in Germany, Radio Deutschland would stop broadcasting to let citizens know something was wrong.

But whenever this happened, the Aspidistra would then start its own broadcast, fooling them into thinking there was no bombing raid.

Ms Newton said: “Aspidistra could receive live programmes from a city that wasn’t being bombed and they would then broadcast the live station itself.

“This meant that someone listening to the radio would notice nothing more than a click when the broadcast changed from the official broadcaster to Aspidistra.”

This had Nazi propaganda chief Joseph Goebbels worried.

“The station does a very good job of propaganda,” he wrote in his diary.

“One can gather the English know exactly what they have destroyed in Berlin and what they have not.”

After the Nazis were defeated, the BBC took control of the Aspidistra for more peaceful ends, broadcasting news around Europe.

In 1986 it was taken over by the Home Office to be used as a nuclear bunker.

If an attack occurred, important figures in government would pack their bags and make their way to the bunker, where they could run the country for the next three months.

The site may not be much use now, but its cold, grey corridors are a haunting reminder of dark days.