Cycling opponents to 2012 bid gather at City Hall

The ride is part of a week-long programme of protests to coincide with the with visit to London of International Olympic Committee inspectors assessing the capital's bid.

Organisers of the ride say that some of London's most cherished cycle routes in the Lower Lee Valley will be closed for years during Olypmic construction work and the Lee's character as a green corridor will be permanently changed.

The special Critical Mass ride is likely to head for the Lee Valley and some of the areas likely to be affected if London's bid is successful.

London Critical Mass is an 'unorganised coincidence' – a ride with no organiser and no set route – which usually starts underneath Waterloo Bridge at 6pm on the last Friday of each month.