Lorry driver Ian Lowther was today jailed for life for the murder of Shipley housewife Mary Gregson 23 years ago.

At a sensational climax to the case which has spanned four decades, Lowther pleaded guilty at Sheffield Crown Court.

Lowther, 47, who was dressed in a black suit and tie, showed no emotion and only spoke quietly to confirm the grim truth about his past.

Mrs Gregson's sister Judith Sykes, sitting in the public gallery, wept and clenched her fists in delight as Lowther finally admitted the brutal killing.

Passing sentence, Judge Michael Mettyear, told Lowther: "Twenty three years ago you robbed an innocent woman of her life.

"You robbed parents of their child, a husband of his wife, and a child of his mother. You took one life but ruined many others.

"Tragically some of Mrs Gregson's family have not survived to see you brought to justice."

Judge Mettyear told Lowther, of Derwent Avenue, Baildon, that it appeared his victim had bravely fought off his unwanted advances, slapping him across the face and kneeing him.

"But you overpowered her. It was a wicked and brutal murder, accompanied by a sexual assault - all this tragedy to satisfy a few minutes lust," added Judge Mettyear.

In mitigation, Simon Lawler QC, told the court Lowther was still at a loss as to explain why he had murdered Mrs Gregson.

He said the former building site worker had lived with the terrible crime on his conscience for the last 23 years, and was relieved when police finally charged him with the murder.

Mr Lawler said: "He must have known that his secret would be discovered. On the day in question, he has an incomplete memory of events."

The court heard, Mrs Gregson set off to work on the evening of Tuesday, August 30, 1977, along Leeds and Liverpool Canal towpath to Salts Mill, Saltaire.

She never arrived, and her body was recovered from the River Aire.

The court was told how Lowther had bumped into the victim by chance after an afternoon's drinking in a Shipley pub, and had tried to put his arm around her.

It was likely she had been assaulted on the towpath and dragged down the embankment, where she was murdered.

She suffered injuries to her face and ears, consistent with being punched or slapped, injuries to her head consistent with it being banged on the ground and she had been strangled with a ligature.

Lowther was interviewed as one of the workers at the nearby building site, and again in house-to-house inquiries. He provided an alibi and was never a prime suspect, but when DNA advances enabled detectives to reopen the case last year, a swab test showed he matched the genetic profile of the killer.

The court heard the chances of somebody else having the same genetic profile were one in a billion.

As far as police are aware, the brutal murder is Lowther's only crime.