G20 police officer accused of manslaughter says he would not have pushed newspaper vendor if he'd known he was unwell

A policeman accused of killing a man during the G20 protests in London told a court he was "sorry I got it wrong" in deciding to strike the man with a baton before pushing him over.

Asked what he would have done if he had known Ian Tomlinson was an infirm long-term alcoholic trying to get home rather than a potentially violent protester, PC Simon Harwood replied: "I would not have gone anywhere near him."

During a full day of sometimes emotional testimony, which saw Tomlinson's family walk out of the public gallery for a period and Harwood's wife, Helen, break into sobs several times, the policeman said he regretted his actions on the evening of 1 April 2009.

He told Southwark crown court: "Now I know all that I know now, and how poorly he was, I am sorry I got it wrong. I should not have hit him with a baton and pushed him."

The 45-year-old, from Carshalton, Surrey, denies manslaughter.

Asked by Mark Dennis QC, prosecuting, whether he accepted he had gone "over the top" having seen footage of Tomlinson walking away from a line of police trying to clear a pedestrian passageway in London's City district, Harwood agreed. He said: "Watching the video, yes, I probably have."

However, Harwood, a member of the Metropolitan police's elite Territorial Support Group public order unit, said repeatedly that he made the best decision he could at the time in the context of a day of disturbances connected to the meeting of G20 leaders in London.

Harwood also rejected Dennis's suggestions that his failure to mention the incident with Tomlinson in notes written later that evening suggested he wanted to cover up what he had done. "No, not at all," he said.

Tomlinson, 47, died soon after collapsing while trying to find a way through police lines to the east London hostel where he lived. Video footage published by the Guardian several days later showed a riot officer, later identified as Harwood, strike Tomlinson on the back of the legs before shoving him hard to the ground several minutes before he collapsed.

The prosecution alleges that the fall caused internal bleeding associated with Tomlinson's liver, which killed him. The effects were exacerbated by Tomlinson's long-standing alcoholism, the court has heard.

At one point several of Tomlinson's children gasped and walked out after Harwood listed a gun among the methods police could use during a hypothetical public order situation to move people like Tomlinson.

Asked what tactics he could use, Harwood listed first a baton strike, then a push, kicks or punches, CS spray, handcuffs, or a voice command. Dennis said: "You have gone straight to violence, force." Harwood said: "No, I have gone for reasonable force."

Asked to cite more options, he named the use of a firearm – at which Tomlinson's relatives left – then use of a shield, or "life-threatening strikes".

Under persistent questioning from Dennis the policeman repeatedly insisted that given the short space of time and situation he had made the right decision on how to move Tomlinson, who he believed was blocking police efforts to clear the passageway.

He could not have guessed Tomlinson's infirmity, Harwood said, saying he would rank him visually at eight on a one-to-ten scale of apparent physical vitality.

Asked why he did not consider, for example, moving Tomlinson away more gently, Harwood said: "I did not have time to consider that option."

Questioned as to why he pushed Tomlinson before giving him a chance to react to the baton, Harwood said: "Because that is the course of action I decided to take." Other officers had already ordered Tomlinson to move and he had not, Harwood added.

Dennis repeatedly challenged Harwood's assertion that he believed at the time he was in a riot, showing videos of the passageway containing relatively few people.

Dennis said: ""I suggest you are not telling the truth at all. This is your last line of defence, having been caught out, on video, acting improperly." Harwood rejected this.

The trial continues.