Ian Smith, the coroner, recorded the verdict after a one-day hearing at Barrow-in-Furness that saw her former husband - and, at one time, murder suspect - Gordon Park tell of the last moment he saw her alive.
In recording his verdict, Mr Smith said the 30-year-old primary school teacher had been the victim of a "nasty and vicious attack" against which she had tried to defend herself.
Mr Smith said of the killer: "If this person is still alive, which 20- odd years later they might not be, I hope they have a conscience and I hope that conscience is troubling them."
At the hearing, Mr Park, aged 54, explained why he waited several weeks before reporting her missing.
Marital problems had forced his wife, a primary school teacher, to go missing before, he said, but she had always eventually returned home.
Mrs Park's body was discovered by amateur divers last year. She was quickly dubbed "Lady of the Lake" but that euphemistic tag rang more than a little hollow as the public heard for the first time the full details of her killing.
Smashed in the face repeatedly with a blunt instrument,carefully trussed up like a joint of beef, the mother-of-three, who was still in her frilly nightdress, was meticulously covered in plastic and canvas, weighed down with metal piping and dumped in the deepest part of Coniston Water. Police arrested Mr Park and charged him with her murder but proceedings collapsed because of insufficient evidence.
Mr Park told the inquest how he last saw his wife alive and well when he left to take their children on a day trip to Blackpool. He said he later arrived home to find their house locked, his wife's engagement and wedding rings on a bedside table - but no sign of her.
He said his wife had left him previously and there had been a custody battle over their three children, but they had got back together again before her disappearance in July 1976.
The coroner asked Mr Park if he recalled where his wife was when he left the family home to drive the children to Blackpool.
Mr Park replied: "Yes - in bed." He added after a pause: "Alive and well."Reuse content