A 20-year-old man accused of the manslaughter of a gay man in central London last year says he hit him to protect his friend.

Joel Alexander, 20, and Ruby Thomas, 18, deny the manslaughter of 62-year-old Ian Baynham, who died after he was attacked in Trafalgar Square in September 2009.

Mr Baynham was knocked to the floor while out celebrating a new job. He suffered head injuries and died in hospital 18 days later.

Mr Alexander, a student, told the Old Bailey yesterday that he had hit Mr Baynham in the jaw because he feared the older man was about to hit Ms Thomas after the pair had an altercation.

She is said to have hurled homophobic abuse at the victim, who then confronted her.

According to the News Shopper, Mr Alexander said: “Mr Baynham threw his right arm and right foot at Ruby in the same motion. His foot hit her on the shin but I did not see his arm hit her.

“I was already moving towards the situation so when I saw Mr Baynham throw his arm and foot at Ruby I lunged at him and threw my right arm into the left side of his face.”

He added that he lashed out to “protect Ruby. I thought she was going to get hit”.

The student said he had never hit anyone before and did not mean to seriously injure the victim. He said he thought he would be injured by Mr Baynham if he only tried to pull him away.

Ms Thomas and Mr Alexander, both from south-east London, deny manslaughter and affray.

The trial continues.