Sorry to do one of those 'at what age' threads. DS1 wants to go into London tomorrow on the tube with some friends for the day. He has been using the tube on his own and with friends, but only locally. We live in the outer suburbs.
My instincts are telling me that it's fine, but I wanted to check in with the Mumsnet collective wisdom, in case I'm about to make a 'What were his parents thinking?' sort of decision.