JUST ten minutes after temporarily blinding a motorist by squirting ammonia into his eyes, a crazed moped rider was involved in a second road rage incident, when he knocked a man out and rode off as if nothing had happened.

These were, said a judge at Croydon Crown Court on Wednesday, two nasty assaults, and he warned 23-year-old Jayce Simms that he is certain to go to prison.

Alan Muir was driving along Stafford Road, Waddon, on June 20 last year when he pulled up at a set of red lights at the Purley Way junction.

Simms, on his Gilera moped, stopped in front of him and produced a small white bottle and sprayed corrosive liquid into Mr Muir's face.

The attacker left the scene unhurriedly, with Mr Muir momentarily helpless.

Soon afterwards, in Lower Addiscombe Road, Croydon, Kevin Field, who was driving with his wife, was "cut up" by Simms.

Mr Field told a jury the rider kept slowing down and stopping and he had to slam on his brakes to avoid hitting the back of him.

"The man got off his bike and came towards me," he told the court.

"I got out and the next thing I remember was lying in the road. I was in a pool of blood and my wife was hysterical."

Witnesses spoke of seeing Simms punch Mr Field in the face.

But, in evidence, Simms, of Regina Road, South Norwood, claimed he thought Mr Field was going to hit him, so he pushed him in the chest.

Simms pleaded guilty to a charge of administering a noxious substance, and also admitted possession of an offensive weapon – a pepper spray – which police found at his home.

He denied causing grievous bodily harm to Mr Field but was convicted.

He was remanded in custody until August 6 when he will be sentenced. Judge Warwick McKinnon told him: "These were two very unpleasant assaults and custody is inevitable."