James Cracknell (and David Walliams) are attempting a cross-continent challenge for Sport Relief 2008, and a Yellowbrick is being used to track their progress from Dover to Africa via rowing boat, bicycle and finally a swim!

James is going to attempt this extreme challenge in the fastest time possible. If conditions are perfect, this could be in as little as seven days - setting a World Record that's extremely tough to beat. James will only be sleeping four hours a night in a mobile home and eating and drinking on the move.