A Brighton student who threw a computer monitor through a bank window as part of last year's G20 protests was jailed for two-and-a-half years today.

Phillip Georgopoulos, 26, said things got "out of hand" on April 1, 2009, when he was captured on CCTV taking part in the protest in the centre of London.

Georgopoulos, who is of joint Greek and American nationality, was trapped outside the Royal Bank of Scotland after police contained demonstrators using the controversial "kettle" technique, Isleworth Crown Court, Middlesex, heard.

He was one of a number of people seen throwing the computer into the bank, which had already had its windows smashed. The damaged windows alone cost the bank £20,000 to repair.

Georgopoulos, of Prestonville Road, later dragged barriers towards a line of police on Threadneedle Street.

Covering his face with a scarf, he then threw a metal scaffolding clip used to connect the barriers, described as being the size of a house brick, at the officers. No-one was injured.

The third year fine art student was arrested that night and later admitted a charge of violent assault, prosecutor Ravinder Johal said.

Sentencing him, Judge Georgina Kent said she noted that the offence had taken place during a "large scale disturbance" and that he was acting as part of a group.

But she told Georgopoulos: "It was a major incident of violent disorder and no doubt others were encouraged by your behaviour."

Richard Parry, mitigating, said his client suffers from attention deficit disorder and dyspraxia, often behaving out of character when under stress. He added: "He gets easily caught up in situations like this."

He said Georgopoulos told him: "We were trapped and it just got out of hand.

"The police were blocking off different exits. I just got kind of crazy. I saw people with blood on their faces, including my friend."

Mr Parry suggested many of the demonstrators were "making a show of themselves" for the many Press photographers and television cameras recording the riot.

He added: "This was an unfortunate incident that arose spontaneously while a crowd was corralled by police, with effectively nowhere to go.

"Although damage was caused to the windows of the Royal Bank of Scotland, there were no injuries. Nobody was assaulted."

He said Georgopoulos did not plan to take part in any further demonstrations, and added: "The banks were the focus of public anger at the time but that is not of course an excuse for what happened."

Georgopoulos had a previous conviction for causing criminal damage and common assault.