The driver of the car which dragged Pc Andrew Harper to his death can be believed when he says “sorry”, his lawyer has said.

Jurors may be “appalled” by Henry Long’s lifestyle, but they were urged to consider his Old Bailey case with “cool heads and dispassionate analysis”.

On the evening of August 15 last year, Pc Harper had been responding to the theft of a quad bike in Stanford Dingley, Berkshire.

As he attempted to apprehend the suspects, his ankles became tangled in a tow rope attached to Long’s Seat Toledo, and he was dragged for more than a mile along country lanes.

He suffered horrific injuries and died at the scene near the A4, jurors have heard.

The driver, Long, 19, and his passengers Jessie Cole and Albert Bowers, both 18, are accused of his murder.

In a closing speech for Long, Rossano Scamardella QC said the “senseless killing of a brave officer” would undoubtedly “stir emotions” and provoke the “deepest sympathy” for Pc Harper’s family.

But he warned jurors: “Emotion is the enemy of clear thinking.

“This is not a trial about whether you like him or not, this is a trial about whether he murdered a police officer.”

On the night of Pc Harper’s death, the defendants had set out to steal the quad bike and then escape in a getaway car with disabled lights, the court heard.

Driving dangerously created a risk of some harm to people they came across that night, Mr Scamardella said.

While the defendants had all admitted conspiracy to steal the bike, only Long had pleaded guilty to Pc Harper’s manslaughter, he said.

Mr Scamardella went on: “When he says sorry, he means it. You can believe him.

“When he says he is ashamed and feels disgraceful, you can believe him.

“When you have behaved as badly as they have, there is a limit to what you can do to make amends. One thing is to accept responsibility.”

The defendants, from near Reading in Berkshire, have denied murder.

In a closing speech for Bowers, Timothy Raggatt QC said: “What happened to Pc Harper was a freak event.

“It was an utterly unplanned event brought about in the circumstances you are now fully aware of, but it was in no way part of anyone’s plan or foreseen at any point prior to the actual moment in which he became entangled.”

He added: “It would be no tribute to the life and service and duty of Pc Harper or his family if you were to do an injustice to any of the three young men.”