A mentally ill man launched a terrifying knife attack on a stranger in the street because he believed he was an evil Nazi, a court heard.

After stabbing Christopher McKeen in the head, chest and arm, Benjamin Emanuel admitted he would have killed him if he had not managed to get away.

Emanuel, 40, was found not guilty by reason of insanity - which enabled a judge to make an indefinite hospital order under the Mental Health Act.

Maidstone Crown Court heard a similar order had previously been made on the paranoid schizophrenic before he was discharged in 2011 because of good progress.

Emanuel admitted he had not taken his medication for more than two months when he knifed the victim on December 4 last year.

Prosecutor Paul Valder said Mr McKeen was walking along Hardres Street, Ramsgate, on his way to Aldi supermarket just before 11am.

He heard a man shouting: "You ****" repeatedly.

"He then felt what he describes as fist blows to the back of his head," said Mr Valder. "He turned around to be confronted by the defendant, who he had not seen before.

"He had both hands above his head and was holding a knife. He went to stab him again. He put his hand up to protect his face and the knife went into his bicep.

"He turned to run and felt another blow to his shoulder. Witnesses had seen the defendant running up behind Mr McKeen with a knife raised above his head shouting: 'I am going to kill you.'"

"The bloke was evil so I attacked him. I have finished. That's my job done. He was a Nazi..." - Benjamin Emanuel

The victim ran to Aldi. The police and ambulance services were called and Mr McKeen was taken to the William Harvey Hospital in Ashford and treated for his wounds, the most serious being a puncture to his chest cavity.

A police officer found Emanuel outside his home in Hardres Street with blood on his hands and shirt.

"He told the officer they were under attack," said Mr Valder.

Emanuel said: "The bloke was evil so I attacked him. I have finished. That's my job done. He was a Nazi."

The jury of seven women and five men was told that most of the evidence was admitted and it only had to be decided whether he "did the act".

Jurors took less than 30 minutes to return the verdict.

Emanuel was jailed for four years in 2000 for possessing a firearm and ammunition with intent.

An indefinite hospital order was made in September 2005 after Emanuel ran at a night warden brandishing a knife at bedsits in Chatham as he "screamed like a banshee" with wide staring eyes.

Judge Michael Carroll said after the latest verdict that his powers were limited but draconian.

"I am absolutely satisfied, looking at your conduct for which you were not criminally responsible, and your previous convictions, there is a high risk of you committing other offences if set at large," he told Emanuel.

"I consider it absolutely necessary for the protection of the public from serious harm to make a hospital order."

It was the best possible place he could return to bearing in mind the recovery he had made so far.

"Hopefully, sooner rather than later, you will be released, perhaps conditionally, into the community," said the judge.

"I believe this is a case where everybody should think long and hard before absolutely discharging you from any mental health order, because you were so discharged and because you declined to take your medication you became mentally ill again.

"I hope that will be borne in mind. We hope that won't happen in the future. We hope you will be able to return to the community, subject to safeguards."