A frenzied knifeman turned a butcher's shop into a bloodbath after he tried to murder four police officers with a meat cleaver, a court heard today.

Christopher Haughton, 33, left three victims with potentially fatal injuries after slashing them with a blade up to ten inches long, it was said.

Other officers were bitten and had missiles launched at them during the rampage in Kingsbury, northwest London, on November 19 last year.

One came inches from a suffering a deadly knife wound to his neck and another had a breeze block thrown at him as he sat in a marked patrol car, the Old Bailey heard.

After he was subdued, Haughton spat blood at officers and lied that he was HIV positive, jurors were told.

“It was perhaps only a matter of very good fortune that some of the police officers escaped with their lives,” said prosecutor Ed Brown QC.

Haughton held a grudge against the police after they arrested him for brandishing a broomstick at neighbours at his bedsit in Hopton Road, Streatham, south west London, weeks earlier.

He had been charged and released on bail and was living with his brother in Milford Gardens, Wembley, at the time of the attacks on the officers.

Police were summoned to a row of shops in Kingsbury Road just before 9am to reports of Haughton causing a disturbance but were unable to calm him down.

“What happened thereafter resulted in terrible injuries that you will hear about,” Mr Brown told jurors.

PC Stephen Barker was first to be attacked by Haughton, who bit him on the arm.

“Such was the defendant's determination, the officer's fleece tore as he pulled away from his clutches,” said Mr Brown.

“The defendant collected masonry and other missiles, which he sporadically threw at officers.

“One such missile struck PC Barker on the hand.”

Haughton then shattered the windscreen of a police car with a breeze block, although the driver, Sgt David Weir, escaped uninjured.

Mr Brown said: “A little further along Kingsbury Road the defendant then entered the Kingsbury Road Halal Butchers.

“It was immediately clear why he had chosen to enter the butchers.

“He found a way through to the butchers' area through the staff door at the back.

“This is where the butchers cut and serve meat. He grabbed one of the knives that were of course by now readily accessible to him on the cutting tables.

“It had a blade of eight to ten inches. Members of staff were still there.

In a series of "frenzied" attacks the defendant caused potentially fatal injuries to three of the officers, coming within millimetres of a fatal injury to a fourth.

Trying to push Haughton with his shield, PC Thomas Harding suffered an injury to his bowel that required emergency surgery.

PC Alastair Hinchliff also had to be rushed to hospital after trying to restrain Haughton.

Mr Brown said: “The defendant slashed him across the left side of his face with the knife, from the temple to the ear, the knife penetrating his face and entering his mouth.

“He continued the knife attack upon the same officer, stabbing him in the upper and lower left arm, causing deep wounds that had the result of exposing the muscle and tendons within.'”

PC Andrew Robb was slashed across the knee as he tried to subdue Haughton with his baton. He received a five-inch wound.

Officers managed to pin Haughton against a display counter and tried to handcuff him, but he lashed out again with the knife at PC Sham Haque.

“The knife was stopped just millimetres from PC Haque's neck,” said Mr Brown.

“It was only prevented from causing what would likely have been a most terrible injury by PC Barker, who grabbed the wrist that held the knife just before it entered Pc Haque's neck.

“The defendant was eventually brought under control but the scene was a dreadful one.

“Officers very badly injured, some critically so, and blood everywhere from their injuries.”

As he was being taken to Uxbridge Police Station, Haughton spat blood at officers and told them he was HIV positive, the court heard.

PC John Charlton was also bitten.

Haughton was diagnosed with paranoid schizophrenia after his arrest, but Mr Brown said he had fully understood his actions.

“His actions were of course determined, dreadful and carried out in real anger,” he told jurors.

“The police had plainly become the object of his anger, perhaps as a result of the events in October.”

Haughton denies assaulting PC Alison Spruce and causing her actual bodily harm during the attack in Streatham on October 9.

He also denies the attempted murder of PCs Harding, Hinchliff, Robb and Haque and alternative counts of wounding each with intent.

He further denies causing actual bodily harm to PCs Charlton and Barker and attempting to cause grievous bodily harm to Sgt Weir.

The trial continues.