A 24-year-old man has admitted killing a father-of-three by stabbing him more than 200 times in a frenzied seven-minute attack.

Ephraim Norman today pleaded guilty to the manslaughter of Andrew Else, 52, on the grounds of diminished responsibility after doctors agreed the brutal attack had been triggered by his paranoid schizophrenia.

Norman followed Mr Else onto a bus and tailed him as he got off in Selsdon Park Road before launching the "savage and unimaginable" attack on April 24 last year, just metres from the victim's home in Woodpecker amount, Forestdale.

Norbury, of Kensington Avenue, Thornton Heath, could spend the rest of his life in a high-security psychiatric hospital after being detained indefinitely by a judge this afternoon.

He can only be released on the order of the Justice Secretary.

The Old Bailey heard Norman had been diagnosed with schizophrenia three years ago but had stopped taking his medication because the side effects prevented him getting an erection.

In the weeks before Mr Else's killing, Norman began hearing voices ordering to him to randomly kill members of the public.

Alan Kent QC said: "On evening of April 24 the defendant left his home address with two knives.

"He boarded a bus and in due course saw Mr Else on the bus.

"Mr Else was a complete stranger to him.

"As the defendant was to later say to police in interview, he chose Mr Else because the voices were telling him to kill somebody.

"When the bus stopped at the place where Mr Else wanted to get off, he did get off, the defendant followed him.

"The defendant stabbed Mr Else, forcing him to the ground.

"Once Mr Else was on the ground the defendant repeatedly stabbed.

When one knife broke Norman drew the other continued stabbing Mr Else until police arrived.

When interviewed by officers he told them voices in his head had told him to kill someone.

He said: "I could not take it anymore because it was constant."

At the hearing he also admitted the attempted murder of a 15-year-old boy in Beulah Hill.

The teenager was stabbed in the head, leaving the blade of the knife lodged in his skull.

Defence and prosecution psychiatrists agreed there was "overwhelming evidence" that Norman was "driven almost wholly by psychosis".

Norman pleaded not guilty to murder and the Crown Prosecution Service accepted a guilty plea to the less charge of manslaughter.