A campaigner facing a 25-year prison sentence in Greece for a crime he says he did not commit has started a hunger strike.
Simon Chapman, 30, from Basildon, Essex, was demonstrating with anti-capitalist protesters at the European Union summit in Thessaloniki in June, when he was arrested.
He was later charged with possessing Molotov cocktails, an axe and a hammer.
But Mr Chapman says they were planted on him by the police, and says he has video evidence to prove it.
If convicted, he could face up to 25 years in prison.
On Tuesday, Dean Robinson, of the Thessaloniki Prisoner Support Group, told BBC News Online that Mr Chapman had been put in an isolation cell after starting his hunger strike.
"We are concerned about him, but he is taking medical advice," he said.
"He knows what he is doing, but we are obviously still concerned."
Many arrested people have sought to discredit the police by alleging the planting of evidence.
But Mr Chapman's supporters say his allegations carry more weight because a cameraman from Greek television was recording the sequence of events.
Jon Silverman, a former BBC correspondent, has seen the footage and says they support Mr Chapman's case.
"The shot of the arrest clearly shows Simon, as he says, with a rucksack coloured blue and purple," said Mr Silverman, wrote in a recent article on BBC News Online.
"The lens then switches to the other side of the road where a police officer is displaying an open black rucksack containing the Molotov cocktails, and other weapons.
"Two police officers carry this bag across the road and dump it on the pavement next to Simon.
"The sequence ends with Simon surrounded by three black rucksacks. Meanwhile, the blue and purple one - his own - has disappeared."
Basildon MP Angela Smith told BBC News Online on Tuesday that she had written to the Greek ambassador about the case and was awaiting a response.
"He must have a fair hearing. He must have proper legal representation and a trial should be held as soon as possible," said Ms Smith.
She said she was concerned about news of the hunger strike.
"It must be very worrying for the family and his supporters and friends," she said.