Mayor Boris Johnson kicks off London cycle event
4 August 2013 Last updated at 10:16 BST
London Mayor Boris Johnson has joined thousands of cyclists taking part in a 100-mile race in London.
As he set off from the Olympic Park in Stratford, east London, he said he hoped to do the race in under 12 hours.
The cyclists will go through Surrey on a route similar to last year's Olympic road race cycling event.
The race is part of a two-day cycling event in the capital.