As the bulldozer got on top my chest was being crushed from the left and the right. I took three last breathes and then I stopped breathing. I was terrified

Pc John Stone

Farm worker Stephen Morgan denies the attempted murder of Mr Stone in the incident in April.

The officer had been called to the Eppynt ranges at Sennybridge near Brecon, where protesters were trying to stop the disposal of thousands of animals culled in the farm disease outbreak.

He told how he saw the bulldozer coming towards him.

"The blade hit the bonnet of my van and pushed me backwards," Mr Stone recalled.

"The wheels squealed because I had the brakes on, trying to stop from being pushed down the hill. I was wasting my time.

Pc John Stone: Terrified

"Then, the back of the van hit something and I was aware of the tracks of the bulldozer catching on the front of the van. It started to climb.

"I could hear shouts and the bulkhead started to crush down on my legs.

"The metal was contorting under the pressure and dirt from the bulldozer's tracks was coming through the broken window.

"As the bulldozer got on top my chest was being crushed from the left and the right. I took three last breathes and then I stopped breathing. I was terrified," said Pc Stone.

He eventually escaped with a fractured foot and bruises. He spent five days in hospital and was off work for four months.

The defendant admits dangerous driving

While 28-year-old Mr Morgan from Llandovery denies attempted murder, he admitted to taking the bulldozer and driving it dangerously.

But he denied damaging seven vehicles endangering the lives of the occupants, and one charge of causing actual bodily harm to an soldier when he is accused of turning the bulldozer on an army checkpoint.

Earlier in the hearing, the jury was told that one policeman smashed the bulldozer window and another sprayed CS gas in order to stop Mr Morgan.

The defendant - found to be over the drink-drive limit - was "incensed" by plans to dispose of animal carcasses at the site, the court was told.

The trial continues.