The city’s Unseen Tours, led by trained guides who are or have been homeless, show visitors a grittier side of some of the city’s most famous neighbourhoods.

On a typical London walking tour, you don’t expect to hear about buildings that are used as brothels, places that are squats for homeless people and doorways that are considered great places to sleep - but this was no ordinary visit.

Our guide Vinny (who didn’t give his surname) was leading an Unseen Tour of Mayfair, London’s most exclusive neighbourhood. Unlike most of the surrounding population, he literally lived on these streets for years, and in a little over an hour he showed us a very different side to Mayfair’s glamour.

The Unseen Tours of London are coordinated by the Sock Mob, a network of volunteers working with London’s homeless population, and led by trained guides who are or have been homeless. Each guide takes groups around “their district” of London and mixes personal stories of life on the street with interesting anecdotes and trivia about the neighbourhood.

I thought I knew Mayfair well but Vinny shared many stories with our group that were both surprising and entertaining. He took us to what is reputed to be London’s most haunted house (in the lavish surroundings of Berkeley Square), he told us about the world’s first telephone call, which was made from Brown’s Hotel, and just off Bond Street he pointed out a little-known piece of graffiti by Britain’s most celebrated street artist, Banksy. But it was Vinny’s insights into the world of the homeless that really struck a chord. He stopped at a few of the many empty buildings (there are around 100,000 in London) that homeless people try to enter in the winter months to survive the cold nights. He also shared his own experiences of life on the street; it was particularly distressing to hear about the occasional abuse he suffered from passers by.

While Unseen Tours offer valuable employment to the guides, there are far more reasons to support the enterprise than merely helping a good cause. By sharing these stories of survival, the guides offer visitors a chance to experience the city from a very unusual perspective. Having seen the brothels next door to the fancy restaurants and the squatters’ homes alongside the millionaires’ mansions, I for one, will never see Mayfair through the same eyes again.