The gathering, which was not officially called a protest, was organised by the campaign group I'm a Photographer, Not a Terrorist. The event brought together thousands of photographers and was the result of an intense campaign by photographers and magazines such as the British Journal of Photography and Amateur Photographer.

It came a year after photographers first gathered in front of New Scotland Yard in February 2009 when a new law came into force making it a potential crime to take pictures of police officers.

Last week, photographers were protesting the use of Section 44 of the Terrorism Act 2000, which gives broad stop-and-search powers to police officers. These powers have been found to be illegal by the European Court of Human Rights. The court said that officers could easily abuse the powers and that, since police officers can stop anyone without the need for suspicion, it was virtually impossible for a member of the public to prove that the powers had been abused.

While a high turnout was expected, organisers were still surprised to see between 1000 and 2000 photographers in Trafalgar Square. 'I think it's the biggest event of its kind,' photojournalist Marc Vallee told BJP. 'Photographers have come here from across the country. It's really heart-warming. I think people are enjoying themselves and also getting the message across.'

He adds: 'You've got professionals and amateurs all expressing their views about Section 44.' You can listen to Vallee's comments on audioboo.fm/profile/1854.

The event, which lasted two hours, was a clear success for photographers' rights. It was covered by news organisations such as BBC, Sky, ITV and CNN.