A Royal Air Force serviceman was acting in self-defence when he knocked an elderly man unconscious, a court heard.

James Sinclair, 24, who is based at RAF Honington, denies causing grievous bodily harm to Thomas Cleary, 72, and assaulting his son Patrick Cleary, 31, in Bury St Edmunds.

Giving evidence on the second day of the trial at Ipswich Crown Court, Sinclair told the jury he saw "an arm coming across" his way from Thomas Cleary and had reacted.

"I did not know if that was a punch or him trying to grab me," Sinclair said.

The jury heard that Sinclair feared for his safety during the incident in Bury on November 23 last year.

Catherine Bradshaw, defending, read out five character references for Sinclair, in which the airman was described as a "mature and hardworking gunner" who is "highly regarded among his peers".

The jury also heard how Sinclair was "passionate about sport" and was an "effective and trustworthy individual".

Cross-examining Sinclair, Phillip Farr, prosecuting, said: "When police arrived at the barracks, one of your responses was 'I know I have done wrong?', why was that?"

Sinclair replied: "I don't have an answer for that."

The court previously heard how Sinclair had asked the father and son for a lighter at the bottom of the steps to the St Andrew's Street car park in Tayfen Road.

Patrick Cleary told the court on Monday that he and Sinclair, of 27 Squadron, had exchanged words before the RAF airman hit him twice.

A taxi driver stopped and Patrick Cleary asked the driver to call the police.

Mr Cleary told the jury he then saw Sinclair, of 27 Squadron, cross back over the road to where his father was still standing.

"He stood there looking at my father," Mr Cleary said.

"Then punched him straight in the face.

"It was like he was punching one of those boxing balls you see at the funfair."

Thomas Cleary was initially taken to West Suffolk Hospital in Bury St Edmunds before being transferred to Addenbrooke's Hospital in Cambridge after a scan found serious bleeding on the brain and a fractured skull.

The trial, which is expected to conclude tomorrow, continues.