"In its simplest form, a tubewalk is nothing more than a walk that starts and ends at a tube station, so all you need to become a tubewalker is a couple of tube stations, a dose of motivation and some time to kill. You certainly don't need someone like me laying down rules.
However, I do need some rules, because I've set myself the challenge of tubewalking the entire tube network, and something that big needs a few rules. I've therefore formulated the following guidelines for my own, personal tubewalk.
Follow the Tube: I'm only allowed to walk between two stations if there is a tube line between those stations.
Walk the Line: If a tube line exists between two stations, then at some point I need to walk between them.
No Repeats: If there is more than one tube line between two stations – for example, Westminster and Embankment are joined by both the Circle and District lines – then I need only walk that segment once. This is to prevent repetitive strain injury and certain madness.
Exceptions: I'm not going to try to walk to Heathrow Terminals 1, 2, 3 or Heathrow Terminal 5, as the airport authority might take a rather dim view of an unkempt and bearded man trying to walk underneath the main runway with a backpack strapped to his back.
Just the Tube: I'm only going to visit stations on the London Underground, so that means I won't be walking the Docklands Light Railway or the London Overground. Besides, I want to leave something to come back for.
This should enable me to walk the entire tube without repeating myself and without missing anything. I'm also going to try to take in as many interesting destinations as I can, because after all, this is supposed to be fun.
This is certainly going to be one to watch as Mark writes with an easy style and often takes a wonderfully sideways look at life. Mark is walking for The Cure Parkinson's Trust so it would be splendid if you pop over and help him out with his fundraising.