A retired teacher kept a "dark secret" for more than two decades after killing his wife and dumping her body from his boat, the Lady in the Lake murder trial heard yesterday.

Gordon Park, 60, killed his "vivacious and pretty" young wife, Carol, in July 1976, Manchester Crown Court heard.

She had been bludgeoned with a murder weapon, possibly an ice axe, and her body wrapped up in the "baby doll" nightdress she was wearing when she was killed.

Mr Park, it was alleged, carefully trussed up her body and dumped it, weighted with stone and lead, into Coniston Water, Cumbria.

The couple, both teachers, lived in a stone house, Bluestones, built by Mr Park in the village of Leece, near Barrow-in-Furness.

But beneath the happy veneer of family life, their marriage was unhappy, a jury was told.

Both had affairs and Carol, then aged 30, had left home once to live with another man.

Mr Park only reported his wife missing six weeks after she vanished, telling neighbours she had left him.

He went on to marry twice more, bringing up the couple's children.

But the remains of the mother-of-three were discovered by chance by amateur divers in 1997, where they had lain for 21 years. If the body had been dumped just a few feet further from shore, it would never have been found, the court heard.

The discovery meant Park's "dark secret" was finally revealed, Alistair Webster QC, prosecuting, told the jury.

''Coniston Water gave up one of the dark secrets of its cold depths, a secret it had guarded for over 21 years,'' Mr Webster said. ''It was a secret known only to one living person - that person is the man who sits in the dock.''

Mrs Park had been bludgeoned with a murder weapon with a sharp edge, and the bones of her face had been shattered.

She had been trussed up in the foetal position and wrapped in a black plastic bag and a weighted rucksack.

Meticulous use of knots and ropes also pointed to the defendant - a climber and sailor with an interest in knots. The same type of knots used to tie up the body had been used at Mr Park's home and his boat.

Also, at a time of great stress, Mr Park allegedly confessed to strangling then battering his wife to two other prisoners.

The court was told that Mr Park was arrested for the first time in 1997, after his wife's body was recovered, and while on remand in jail made the confession.

The couple had been married for nine years and were, on the face of it, a normal quiet family. "But beneath this apparently happy veneer, all was not as it seemed," Mr Webster said.

Mrs Park was described as petite and pretty, a good musician with a bubbly and vivacious personality.

Mr Park was controlled and careful and both had "wandered", the court heard.

After a bitter custody battle, he had been awarded care of the three young children.

But his wife could not live without them and returned to the marital home.

She vanished on Saturday, July 17, 1976, at the start of the school holidays.

Mr Park later told police he had taken the children on a day trip to Blackpool, leaving his wife at home.

When he returned she had gone, leaving her wedding and engagement rings and her clothes behind.

But he did not report her missing to police until six weeks later, via his solicitor.

Mr Park, who denies murder, left court with his third wife, Jenny. The hearing was adjourned until today.