Just off the road between Hampstead and Highgate, perching resplendently on a ridge that offers a commanding view over inner London’s rooftops and skyscrapers, the Blue Badge tourist guide and his or her clients will find one of London’s ‘hidden gems’: Kenwood House.

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.