I've had similar paragraphs in contracts but have been lucky in that I've moved into roles in different inducstries.
Some interesting thoughts here:
http://www.ukbusinessforums.co.uk/fo...p/t-16327.html
Jef - Gardening leave usually refers to you serving your notice but spending the time at home and not actually working as your outgoing employer doesn't/ can't/ won't assign you any more work. Best to get it when the weather is good!