Most London Blue Badge Tourist Guides have had clients who want to get a snap of themselves by a red London phone box, often with Big Ben in the background. It is almost a rite of passage for a visitor to London and so the red boxes at the end of Whitehall often have long queues of people waiting outside for the chance to take a picture of themselves. The phone booths are rarely put to their original use – namely, to make phone calls. Now, of course, the mobile phone reigns supreme and most people have a smartphone in their pocket.

Tourist guides are normally concerned with what is above ground, but London also has a fascinating underground story. As well as the famous buildings you can see on the surface – Westminster Abbey, Saint Paul’s Cathedral, Buckingham Palace, and the Tower of London – London has a network of underground sewers and rivers that repay close attention.