Sometimes when gadding about in central London I am set back by a station closure or some other incident that requires me to find another station. In those cases I don't care if the station is on the same line (I can always connect to resume my journey), the paramount concern is walking time.

So what I am after is a guide to the London Tube that contains the average walking time from station to station.

While I am a London area resident the same issue confronts visitors; indeed, in the case of a visitor, their need is more acute because they have no clue about which tube stations are in the general area.

Question: how can I obtain a walking map of the London Tube system? While the immediate interest is London, I would be delighted to obtain other cities (Birmingham, Edinborough, and so on) if they exist.