An off-duty policeman had his bicycle rammed by a car when he asked the driver to stop, a court heard today.

Cycling Stephen Hynes grabbed motorist Guy Cozon by the shirt after the Mazda MX5 rolled over his front wheel.

The policeman was dragged along before Cozon nearly crashed into a fence and then sped off along Marquis Lane in Harpenden, the jury at St Albans Crown Court was told.

Prosecutor Louis French said it was 8pm when local resident Mr Hynes was riding his bike along the road, which is a dead end.

"He recalls a car coming from the dead end and it was going at speed. There was a screeching noise and the wheels were spinning. It screeched to a halt close to stables near a railway bridge," said the prosecutor.

Mr Hynes, who had a powerful lamp on the front of his bike, went over to the car and is said to have told Mr Cozon: "Wind your window down. What are you doing? Why are you speeding?"

The prosecutor said he got no response and the car was "revved hard and loud" and moved slowly forward.

When Mr Hynes told him not to move and that he was calling the police, the driver allegedly moved forward with his engine revving and rammed the bike, before driving off while the officer tried to hang on.

Guy Cozon, 34, of Salisbury Road, Harpenden, denies dangerous driving on Thursday 19, September 2013.

He was arrested on Saturday, September 21, after Mr Hynes had recalled some of the car's registration plate.

In an interview, Cozon told officers he had suffered a puncture and had replaced a tyre. He said he had gone to the quiet lane to test the grip on the new tyre when he had encountered the cyclist.

Cozon agreed there had been shouting and said that the cyclist had moved his bike in front of the car.

He said he told him: "Just move your bike and let me go."

At most, the bike was touched by the bonnet of his car before the cyclist had grabbed his shirt and ripped it, he said.

Case proceeding