In 1992 in San Francisco cyclists started riding together monthly to assert themselves as traffic in a ride that became known as Critical Mass. Since then Critical Mass has spread to over 300 cities around the world and become a common feature of protest culture.

To celebrate 10 years of critical mass, over 800 cyclists took to the streets in London last year with a bike samba band, live guitar from a rickshaw, multiple sound systems, mad bikes the like of which have to be seen to be believed. It was massive, and it happened again on Friday April 29. At least 500 cyclists, rollerbladers and skateboards joined the 11th Annivesary in London. There will also critical masses in Glasgow, Liverpool and Nottingham - and probably other cities around the country as well.

On Saturday 30th April there was a successful mass "against climate change, pollution and the G8" in Worthing, Sussex. Meanwhile, in Sheffield on June 11th and the 15th there are more rides to coincide with an anti-war demo and the G8 meeting of Justice and Interior Ministers in Sheffield taking place 15th/17th.