The son of a woman killed when her car was crushed in a head-on collision with a tractor in Norfolk has described how he battled to save her life.

Mother-of-two Rebecca Brown, 43, died in the collision on a country road near Castle Acre.

Henry Bett, 26, son of the county's police and crime commissioner Stephen Bett, was driving the Fendt tractor on his way home from work on a nearby farm. He denies causing death by dangerous driving.

Tom Brown, who was 17 at the time, told how he had been in the passenger seat of his mother's Fiat people carrier when the crash happened.

In a video interview played to Peterborough Crown Court, sitting in Huntingdon, he said: 'I remember seeing the tractor and thinking 'what the hell is he doing' because he was in the middle of the road.

'After that I can't remember anything because I just blacked out.'

Mr Brown said he came round to see his mother's face covered in blood. His father, who sat in court, appeared emotional as he recounted the ordeal.

Mr Brown said: 'I started to panic, I was just trying to wake her up.

'I rang 999 but I couldn't speak because I was too upset. I was trying to wake her up, hold her and speak to her. I tried to give her CPR and some passers-by came and tried to help.'

Earlier prosecutor Simon Wilshire told the court that witnesses said the tractor had been speeding in the moments before the collision on the West Acre Road near Mrs Brown's home village of Castle Acre on December 4, 2013.

Tests later found that Bett had taken cocaine between 12 and 24 hours before the incident and may have been suffering the after effects of the drug.

Mrs Brown died within minutes of the collision.

Bett, of Hall Lane, Thornham, Norfolk, told motorists who stopped at the scene that he had tried to avoid a collision.

Bett broke down in tears in the dock as Mr Brown gave evidence.

Pc Jeremy Blamire, the first officer on the scene, said Bett had seemed 'distraught' but there was nothing to suggest he was unfit to drive and he passed a breathalyser test.

He added that he had arrived at the scene travelling in the same direction as Mrs Brown.

'The sun was in my eyes,' he said.

The trial is expect to last three weeks.