Following in the footsteps of her successful BBC2 1998 series, Coast to Coast, As the Crow Flies describes Janet Street-Porter's attempt to walk the 350 miles from Edinburgh Observatory to Greenwich Observatory - in a dead straight line. She discovers a new way of walking - the OS map isn't quite so handy when you can't stray off a line you've drawn on a map. What's more useful is a heavy clearing stick, the power of persuasion and the patience of a saint.