A schizophrenic stabbed a father to death because he was convinced MI5 had sent him to be an assassin, a court was told.

Daniel Quelch, 34, a father of three, was found with horrific injuries after he was repeatedly knifed at his home as his children slept.

Benjamin Frankum, 25, from Littlehampton, was arrested at the scene, where he told police he had been sent to kill Mr Quelch.

A judge yesterday ruled him unfit to stand trial for murder but a jury was sworn in at Reading Crown Court to decide whether he was responsible for killing Mr Quelch.

The court heard Mr Quelch was staying at his parents’ bungalow, where his three children, aged eight, four and two, had been having a sleep-over party.

Nigel Daly, prosecuting, opening his case to the jury, said: “What happened is everybody’s worst nightmare.

“Daniel Quelch was asleep in bed with his two-year-old son. Benjamin Frankum, a paranoid schizophrenic, came into his house. They did not know each other. And Mr Frankum stabbed Mr Quelch 82 times.

“The motive? There isn’t one. There is no evidence he knew Mr Quelch. It was a totally motiveless crime.”

Mr Daly said Frankum had been in and out of hospital with mental illness, having been sectioned in 2001 and diagnosed as a paranoid schizophrenic.

Authorities allowed him to live in supported accommodation early in 2007 but he failed to take his medication, as he had failed to do many times in the past when released from hospital.

Early on August 23 last year, Frankum broke into the house near Maidenhead, Berkshire, owned by Barbara Quelch, mother of Daniel Quelch, a landscape gardener.

He stabbed Mr Quelch to death, then gave his children cola and yoghurt when they were woken up by the attack, the court was told.

Frankum was seen in his boxer shorts covered in blood by Barbara Quelch as she drove back from walking her dogs at about 7am.

He banged on her car door saying he was from the police but she did not believe him and called 999.

He was seen to crouch down with a pile of his bloodied clothes and then throw a knife into a nearby hedge, the jury was told.

Mr Daly said Frankum told paramedics and police at the scene: “You don’t want to go in there, there’s stuff you don’t want to see.

“There’s a bloke in there, I’ve stabbed him about 10 times. He wouldn’t die. There are about three children in there. They’re all OK.”

He told police that “MI5 sent him down to kill Danny”, adding, “can you get me a can of coke – there are some in the fridge?”

Mr Quelch was found in a pool of blood on the kitchen floor with his throat cut.

The case continues.