A police officer accused of killing a newspaper seller at a G20 protest told a court he was wrong to have hit and pushed him.

PC Simon Harwood, from Carshalton, hit Ian Tomlinson with a baton and pushed him to the ground during the protests in central London in April 2009.

The father-of-nine walked a short distance before he collapsed and later died.

PC Harwood, 45, an officer with the Metropolitan Police's territorial support group, denies manslaughter on the grounds that he used reasonable force.

At his trial at Southwark Crown Court on Tuesday, Mark Dennis QC asked PC Harwood: "You do now accept that what you did in relation to Mr Tomlinson was wrong?"

The officer replied: "Like I said, now I do, but not at the time."

He said: "Now I've seen all the evidence and I know how poorly Mr Tomlinson was, I'm sorry that I got involved, I shouldn't have hit him with a baton and pushed him."

Giving evidence earlier, PC Harwood said he thought Mr Tomlinson was deliberately obstructing the police.

He said: "I believed he was doing it on purpose. From what I saw he looked like he wasn't going to move and was looking at the police as though he wanted them to move him away."

He said he pushed Mr Tomlinson, who was walking away from a police line at the time, "firmly" after the baton strike but did not mean to push him over.

PC Harwood told the court that before coming across Mr Tomlinson he thought the protesters were targeting him after he tried to arrest a man for scrawling graffiti on a police carrier.

He said: "They seemed to be goading me and shouting at me, pointing their fingers at me."

Mr Dennis told Harwood he had adopted a "strike first, ask questions afterwards" approach. He was caught on camera hitting and pushing Mr Tomlinson.

The trial continues.