Inside the secret network of underground bunkers designed to save Londoners from nuclear annihilation
THIS is London's last line of defence: a network of secret underground bunkers designed to be used in the event of a nightmare nuclear attack.
Hidden deep beneath our feet, these bunkers would become a desperate last refuge for any survivors caught up in the apocalyptic horror.
Most people don't even know they they exist, but the secret hideouts would have saved thousands of lives if London ever fell victim to deadly nuclear strike.
The most famous of the bunkers was built during the late 30s, before nuclear weapons had even been invented.
The Churchill War Rooms under the Treasury were used in the early days of World War 2, when the government relocated to the underground shelter.
Throughout the war, the bunker was kept hush, but the public were let in on the secret once the conflict ended.
It has since been turned into a museum, with the Cabinet War Rooms open for members of the public to snoop around.
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But reports that there are many more bunkers which remain shrouded in secrecy - and off limits to the public.
A mysterious bunker deep under the Ministry of Defence is believed to offer a final hiding place for the government in the event of a nuclear war.
Rumour has it that the secret shelter is connected to Downing Street via a hidden tunnel, and other claim it is connected to a tube station.
The government denies it is connected to the underground, but the bunker definitely exists.
Nearby, the Admiralty's Citadel was built to be used in the event of a Nazi invasion.
The fortress is no secret, but not much is known about the hidden network of tunnels which link it to other sanctuaries.
Meanwhile, the tube network is known to be home to other secret shelters, such as the abandoned station converted into a military bunker.
Down Street, a disused station near Hyde Park, was developed into a bunker in 1939, which Churchill used whilst his War Rooms were being renovated.
And deep-level bomb shelters have also been built into a number of other stations, originally as a measure to withstand Hitler's Blitz.
A bunker beneath Chancery Lane station, in the city's centre, was developed into a communications facility designed to withstand a nuclear war.
But the hidden base was abandoned in the 1980s, and - like many disused bunkers - was put on the market as a storage space for Londoners to buy.
However, if World War Three really does break out, the PM and co won't be hanging around the capital.
Their emergency HQ is actually located in Wiltshire, with an underground nuclear bunker tucked away beneath an RAF base at Kelvedon Hatch.
Earlier this month, we exclusively revealed why 2017 is set to be such a dangerous year - thanks to mounting global threats.