On the night of the Olympic opening ceremony several hundred cyclists were kettled by police when they ventured too close to the stadium. They were taking part in Critical Mass, a leaderless, spontaneous bicycle ride celebrating cyclists’ right to use the road that has taken place every month for the past 18 years.

Olympic exceptionalism meant that the police were able to impose a section 12 order (which allows them to control ‘processions’ in order to ‘prevent serious public disorder, serious criminal damage or serious disruption to the life of the community’) over half of London. The Critical Mass cyclists were warned that they wouldn’t be allowed north of the Thames, or anywhere near the stadium in which Britain’s cycling heroes were taking their turns.

When the peloton did cross the river the policing was robust. Passing cyclists who had nothing to do with Critical Mass were knocked off their bikes and detained. In the end 182 cyclists were arrested and kept on buses for hours without water or access to toilets. Photos, fingerprints and DNA were taken. Nine cyclists were eventually charged with breaching the order.

The police have argued that Critical Mass is a planned protest, and that as such the organisers should have submitted the route and sought approval before they set off. In 2008 they took to the courts to try to outlaw the rides. Critical Mass argued that it had no leaders and no planned routes, and the House of Lords agreed, finding that they didn’t need to notify police in advance as the rides were ‘commonly or customarily held’. (The same couldn't be said of the Olympics.)

Yesterday – a week after Boris Johnson announced a £1 billion scheme to usher in ‘a new age of the bike’ – five of the Critical Mass nine were convicted of breaching section 12 of the Public Order Act. The next Critical Mass will take place on 29 March.