Urban explorers enter London's landmarks

More than 300 of the capital's most famous landmarks are being secretly entered at night by groups of "urban explorers".

London is at the epicentre of the rapidly growing global movement, described as the practice of entering unseen or off-limits areas for the thrill of discovery.

Bradley L Garrett, 30, a PhD student and documentary maker who is an explorer himself, said it is likely there are more than 3,000 explorers operating in Britain alone.

"I can't discuss most of the buildings we have been to as we are still exploring them. But in the past year we have been inside the Battersea Power Station and Millennium Mills and on top of St Paul's Cathedral, the British Museum and Heron Tower," he said. "We are making life and death decisions after work every day.

"There is nothing like the experience of hovering on a crane looking down on the city or below ground, watching the sewage passing by," he added.

Among the group that Garrett operates with - who go by the name London Consolidation Crew - is a London bus driver, a jobcentre worker and a special constable.

They have links to other "crews" in Paris, Milan, New York and Chicago. The group scour archives and old maps for forgotten entry points. They then share their findings with other groups across the world on secret online networks. The group said they never vandalise, damage or steal. Garrett added: "Where we need to pick a lock or disable security systems, we always put it back the way it was."

The Met Police refused to comment on the activities of urban explorers but their involvement seems limited to one occasion in April last year when four men were arrested exploring disused Tube stations. He said: "The crew most often sneak into buildings without police or security ever knowing we were inside. You have to have a heightened sense of awareness not to be caught or killed."