A policeman only punched a motorist, who died shortly afterwards, to prevent him from driving into colleagues, a court heard yesterday.

Pc Robin Shane, 31, hit Robin Goodenough in the face, before the 26-year-old was dragged out of his car and suffered a heart attack after smashing his chin on the road in Alma Place, Oxford, London's Old Bailey was told.

Shane is standing trial with Pc John Shatford, 32, accused of assault occasioning actual bodily harm during the arrest just after midnight on September 27, 2003.

Both deny the charge.

Jurors were read a statement made by Shane that night describing his colleagues trying to pull Mr Goodenough out of the car "with a great sense of urgency".

"They were shouting 'Get out of the car.' They appeared to be in a state of panic," he said.

"I could hear the Astra was still switched on. It occurred to me that PC Shatford was scared he would start the vehicle. I was seriously concerned for my colleagues' safety.

"I realised we needed to control him. I decided a distraction blow would be the most appropriate tactic. My only option was to administer a punch."

He hit Goodenough twice, but said he did not believe he was seriously hurt by the blows.

The statement said Goodenough's eyes were closed and blood was pooling by his cheek, but "the lack of any pain when I struck him led me to believe he was high on drugs".

Shane said there was a graze on his fist where he had hit him.

"The ambulance arrived quickly. Someone said, 'He's stopped breathing.' I was told the driver was in cardiac arrest.

"I was struggling to understand how the man had come to be in such a poor state of health."

The trial continues.