A brave police officer was stabbed in the chest as he tried to stop a violent knifeman in the street.

Ayhan Kilavuz, 37, who suffers from mental illness, ran around city centre streets brandishing the large kitchen knife and threatening to kill English people.

The shocking scenes were witnessed by terrified shoppers on a sunny Saturday morning last summer.

PC Leigh Cobb was one of four officers called to Western Road in Hove after Kilavuz, a Turkish national, started chasing after frightened passers-by who ran for their lives.

Kilavuz lashed out at PC Cobb, 28, but the officer escaped being seriously wounded because he was wearing a regulation stab vest, which was ripped by the knife.

The courage of the officer and his colleagues as they put themselves in danger to protect the public was praised by Judge Anthony Scott-Gall at Lewes Crown Court.

Kilavuz, of Brunswick Road, Hove, was charged with attempting to wound PC Cobb with intent to cause him grievous bodily harm and making threats to kill passerby Stephen Booty.

He pleaded not guilty by reason of insanity.

During a trial the jury heard Kilavuz, who has been held in a secure mental hospital since his arrest, has been assessed by two psychiatrists who concluded at the time he was suffering from a severe psychotic illness. Kilavuz told doctors he believed smoking cannabis had caused his mental condition.

The prosecution and defence barristers both invited the jury to return a verdict of not guilty due to insanity. The jury returned with the verdict after retiring for less than five minutes.

The court heard the drama started as about 11am on July 7 when Kilavuz, who has been receiving treatment for mental illness since 2000, visited his brother, who works as a barber in Preston Street, Brighton.

Kilavuz, who was wearing a white vest, shorts and carpet slippers, then started walking along busy Western Road towards Hove.

Moments later he confronted two men and asked them if they were English before chasing them. Stephen Booty, the manager of the Robert Dyas Store, in Western Road, and his colleague Francis Olszanski ran for their lives after noticing the blade glinting in the sunlight.

Witnesses heard Kilavuz shout: "I am going to kill all you English."

When Kilavuz reached Waterloo Street the police arrived. PC Cobb was behind the wheel of a patrol car, accompanied by PC Liz Simpson.

When Kilavuz saw the patrol car stop in the centre of the road he charged towards the vehicle and jumped on to the bonnet and then the roof. He repeatedly hit the windscreen with the knife in a frenzied attack causing the screen to smash while the officers were trapped inside.

Two other officers, PC Sue Pryor and PC Harry Lennard, arrived and all four tried to surround Kilavuz, who was still wielding his knife.

Captor spray was used on him but to no affect.

Kilavuz continued to lash out with the knife. When PC Lennard tripped and fell to the ground Kilavuz moved towards him.

PC Cobb, fearing for his colleague, ran towards the knifeman in an attempt to distract him from PC Lennard.

Kilavuz stabbed him in the chest, but the blade did not penetrate the stab vest the officer was wearing.

Mr Barton said the stabbing action would have caused the officer serious injury if he had not been wearing a stab vest.

During a violent struggle, Kilavuz stabbed himself in the chest and the knife broke in two.

PC Cobb was treated at the scene but none of the officers or members of the public were hurt.

The jury was showed the damaged stab vest and a series of graphic photographs taken by Brian Butterworth, who witnessed the scene from his fourth-floor flat in Waterloo Street.

Kilavuz, who is divorced, did not give evidence.

Kilavuz will be sentenced under the Mental Health Act on February 25.

Judge Scott-Gall said the incident must have been terrifying. He said: "Were PC Cobb not wearing a stab-proof vest the attempt to cause him grievous bodily harm might have proved fatal."

He told the jury Kilavuz would be detained in a secure unit for many years to come.

After the hearing PC Cobb said: "We are paid to protect the public and that is exactly what we did."