Thanks for the reply Derek. Unfortunately, the pothole was in the middle of a busy London street, so I couldn't stop and take photos. I live in Chepstow, so I suspect it would be fixed by the time I had chance to go back. I've sent an enquiry to Transport for London, though, who are responsible for the trunk routes, because it was practically impossible to avoid, and very dangerous. Looks to me like someone forgot to replace a manhole cover
