The police officer accused of the manslaughter of newspaper seller Ian Tomlinson accepted on Tuesday that he was "wrong" to have hit and pushed him.
Continuing his evidence at Southwark Crown Court, Pc Simon Harwood said if he had realised Mr Tomlinson was walking away from police lines at the time he "would not have gone near him".
Pc Harwood hit Mr Tomlinson with a baton and pushed him to the ground during the G20 protests in the City of London in April 2009.
The father-of-nine was able to walk a mere 75 yards before he collapsed and later died.
Mr Tomlinson was walking away from police lines when he was hit and shoved to the ground, but at the time Harwood said he thought he was being deliberately obstructive.
Patrick Gibbs QC, for Harwood, asked him: "If you knew then what you know now from looking at the footage, would you have hit him with your baton?"
The officer replied: "I would not have gone near him."
He also said he would not have pushed Mr Tomlinson if he had known that he was drunk at the time.
Mr Tomlinson's son, Peter, and widow Julia have campaigned since 2009 for answers over the newspaper seller's death
Earlier, the court heard he felt "shock" when he saw video footage of his encounter with Mr Tomlinson being shown on television.
He said he felt: "Shock at the fact that it was on television and the horror of actually thinking it could be me there and what it could lead to."
Mr Dennis asked Harwood: "You have to be aware that the person you are dealing with may, for example, have a frailty?"
He replied: "Yes."
Looking at a photograph of Mr Tomlinson, who was an alcoholic and slept rough for a number of years, Harwood said he would rank him as an eight out of 10, where 10 was a fully fit person.
Mr Tomlinson's family walked out of court as Harwood went through a list of his options when he came across the 47-year-old.
He listed using a baton, a push, kicks, punches, CS spray, handcuffs, his voice or firearms.
Harwood's wife, Helen, began crying as the questioning continued.