Pc Stephen Norman arrives at Aylesbury Crown Court

Pc Steve Norman, 44, was charged following the death of Oxford Brookes University student Emily Higson, 22, outside a bar on 16 November last year.

Ms Higson was crossing the road after a night out when she was hit.

Pc Norman, who pleads not guilty, was answering a 999 call after a robbery and had his lights and sirens on.

Prosecutor Mark Norman told a jury at Aylesbury Crown Court that the sociology and anthropology student was thrown into the air by the force of the impact and landed 75ft away.

He said witnesses differed on whether she ran or strode into the road, but added: "She moves out, straight out. She appears not to have heard the sirens.

"She doesn't wait for the crossing, she moves straight out into the road."

Ms Higson died in hospital shortly after she was knocked down

Pc Norman told fellow Thames Valley Police officers in an interview that he did not see Ms Higson coming out into the road until she was about 10 or 15m away.

But Pc Claire Argent, who was in the car with him, said Emily took her first step on to the crossing when the car was about 40 or 50 metres away, Mr Norman said.

Pc Norman braked and swerved but the student was hit by the front nearside of the patrol car, which he admitted was doing between 50mph and 60mph.

The officers stopped and tried to help Emily but there was a "violent confrontation" with angry people at the scene.

Mr Norman told jurors that one of the questions they needed to ask themselves in trying the case was "did the defendant's driving fall far below the standard of a competent and careful driver?"

He said police were entitled to ignore traffic regulations "provided always that it is safe and necessary to do so".

The trial continues.