It's never been done before and it could become a World Record but more importantly the endeavour will raise money for The Rob Knox Foundation which campaigns and educates against street violence and knife and gun crime and creates opportunities for young people.
Joe's the one who has to do the 24 hours. You can book on to one or more of five 4-5 hour tours at £20 each — choose from Street Art, East London, Southwark, City and Westminster. It starts at 8am at Aldgate East tube on Saturday 25 August (that's a bank holiday weekend so plenty of time to recover) and finishes at 8am the following morning in Trafalgar Square.
We can imagine that he'll need lively support from an interested crowd every step of the way. Questions and conversations will help keep him going with the guiding throughout the day and especially the night. Pick a tour, make your friends come along and email email@example.com to book your places.
If you can't join Joe on his 24 hour jaunt you can still support him by making a donation at his JustGiving page.