A retired pig farmer from Worcestershire "got away with murder" for nearly 40 years after dumping his wife in a septic tank while having a "long-standing affair", a court heard.
David Venables, 89, is alleged to have killed "prim and proper" Brenda Venables.
Her remains were discovered in the underground chamber, in what was once a "rough", overgrown and "secluded" spot - 37 years after she vanished.
Michael Burrows QC, opening the prosecution case at Worcester Crown Court on Monday, said Venables had been in an on-off relationship with his mother’s former carer Lorraine Styles in the run-up to his wife’s disappearance.
The Crown alleged Venables, then 49, killed his wife, 48, and dumped her body in a septic tank in the grounds of "remote" Quaking House Farm, off Bestmans Lane, Kempsey, Worcestershire, where the couple had lived since 1961.
Mr Burrows said: "The truth, say the prosecution, is that it was David Venables who killed her.
"He wanted her out of the way: he wanted to resume his long-standing affair with another woman."
'It was the perfect place and he got away with murder', court told
Mr Burrows continues: "He knew about the septic tank in its secluded location.
"It was for him almost the perfect hiding place.
"It meant he didn’t have to travel and risk being seen making a suspicious journey around the time of her disappearance or risk being seen disposing of her body somewhere else.
"And, of course, even if someone did think to look inside the tank, her body would be hidden from view.
"And for nearly 40 years, it was the perfect place and he got away with murder."
The jury heard Venables’ affair with Ms Styles started "around 1967", and continued on and off.
Mr Burrows said that by 1981, Ms Styles had “doubts again about David Venables’ feelings for her”, but that the farm owner rekindled the extramarital affair over that Christmas and New Year, just months before his wife vanished.
'Some people thought she had committed suicide', court hears
Jurors heard Venables reported his wife missing at Worcester police station May 4 1982.
"He said he had awoken that morning and that his wife was not in bed nor in the house,” said Mr Burrows.
"He also said she had been depressed."
A police investigation failed to find any trace of Mrs Venables, while "some people thought she had committed suicide".
By 2019 Venables had sold the farm to his nephew, and it was in July that year that contractors, clearing out the septic tank, found bones including a human skull.
"DNA testing showed the remains were those of Brenda Venables," said Mr Burrows.
Venables, on bail, has been sitting in court wearing a suit and tie and earphones in order to follow proceedings, jurors have been told.
The pensioner, of Elgar Drive, Kempsey, denies murdering his wife between May 2 and May 5 1982, and the trial, scheduled to last six weeks, continues.