A homeless man has been jailed for life after confessing to the "brutal" murder of an Irish man in London dating back almost 40 years.

Anthony Kemp was 21 when he attacked Dublin-born Christopher Ainscough with a marble ashtray after they met on a night out in December 1983.

Kemp, now 59, pleaded guilty to murder and was sentenced to life with a minimum term of 15-and-a-half years at the Old Bailey.

Judge Mark Dennis QC told him: "This was a wholly unjustified, brutal killing that led to the death of a harmless, well respected, good natured man who had befriended you and caused you no harm."

The judge said the "sustained assault on the defenceless victim" was born out of Kemp's intoxication and violent temper triggered by the perceived actions of the victim.

It was a "dreadful act of violence" that would have been on Kemp's conscience ever since, the judge said.

The court had heard that Mr Ainscough, 50, had invited Kemp back to his home in Kilburn, north-west London, in the early hours of the morning and was on the sofa when he was attacked.

His body was discovered by police after he failed to turn up to work at a restaurant in the city.

He had suffered devastating head injuries, including a fractured skull from being hit with a marble ashtray weighing 2.4kg, which was found at the scene.

Mr Ainscough was gay and had been warned about inviting people he had just met to his flat in the past, the court heard.

The original murder investigation was closed in 1985 after no leads were found.

On 28 July last year, the cold case was reopened when Kemp made a confession.

He turned up at Chiswick police station in west London and began to throw stones at the window, before an officer came out to speak to him just after 4am.

Kemp told the officer he had murdered someone 40 years ago, saying he had "bashed his brains in" over an argument.

He said: "I'm not going to live on the f****** streets, that's a fact. I'd rather the Government look after me.

"I'd rather do the last few years of my life in bang-up than sleep on the streets."

He added: "For 40 years I got away with it and now I'm owning up to it."

Kemp told police he did not know what had happened to spark the row.

He said the victim had been "sparko" after the first blow and he was "at his head going bosh, bosh, bosh".

Before leaving the flat, he spent five minutes using a cloth to wipe down everything he had touched, including the ashtray, a glass and a door handle.

Kemp, who was previously an alcoholic and heroin user, retracted his confession three days later after being released on bail.

He blamed the killing on his accomplice in an aggravated burglary in 1988, who had killed himself in prison.

But police matched Kemp's DNA to that left on a cigarette butt in an ashtray on a coffee table in Mr Ainscough's sitting room.

The court heard that Kemp had previous convictions for burglary and possession of a knuckle duster in 1980.

In 1988, he smashed up a flat in Northumbria which he shared with a girlfriend who said he had a "violent temper".

He was jailed for seven years for an aggravated burglary the same year.

Kemp and his accomplice, who disguised themselves as chefs and wore tights over their heads, forced their way into their victim's flat and punched and hit him.

In a victim impact statement read to the court, a close friend of Mr Ainscough described him as like one of her family.

Dublin-born Christopher Ainscough was 50 when he was murdered

The elderly woman, who asked not to be named, said: "Chris was a kind, generous, caring and funny man. We just adopted him.

"He was charming and had the extraordinary ability to get on with anybody and everybody.

"What someone did to my beautiful friend was devastating."

Kemp killed a "very special person" as if it did not matter, then "walked free" for almost 40 years, living the life her friend should have had, she said.

She added: "The brutality of what was done has haunted me."