A protester has claimed he was arrested for wearing a “Plasticine Action” T-shirt.

Miles Pickering, an engineer from Brighton, was one of 532 people arrested at a demonstration in Parliament Square, central London, on Aug 9.

He had been arrested under section 13 of the Terrorism Act 2000, which makes it an offence to wear anything supporting a proscribed organisation.

Mr Pickering was not wearing clothing supporting Palestine Action, but a T-shirt declaring opposition to “AI-generated animation” complete with the stop-motion character Morph giving the thumbs up from inside the letter ‘O’.

Palestine Action was proscribed by the Government in July after admitting that activists broke into RAF Brize Norton. Membership and support of a proscribed group can carry sentences of up to 14 years in prison.

The protester later told The Guardian that an officer had glanced at his top and told him “right, you’re nicked” before taking him to Scotland Yard. He said a throng of cheering supporters had gathered by two gazebos where police were processing those arrested.

“They were taking photos of me, and everyone was laughing at how silly it was that I was getting arrested for being a plasticine terrorist,” he said.