Rock climbing usually involves getting from the bottom of the giant face of rock to the top of it and last time I checked London has a distinct lack of fuck off walls of rock. Unfortunately you've got a good few hours sitting in a car if you want to get to good crags. Southern sandstone (around Tunbridge Wells) is probably closest but that's pretty limiting (Max height is roughly 10m, no leading, can only climb when it's dry).
Rock climbing usually involves getting from the bottom of the giant face of rock to the top of it and last time I checked London has a distinct lack of fuck off walls of rock. Unfortunately you've got a good few hours sitting in a car if you want to get to good crags. Southern sandstone (around Tunbridge Wells) is probably closest but that's pretty limiting (Max height is roughly 10m, no leading, can only climb when it's dry).