A retired industrialist has admitted killing his wife in a frenzied stabbing attack at their Warwickshire home.

Kenneth Mack, 82, had denied murdering Lorraine Mack, who was stabbed 50 times in December 2006, at their home in Ullenhall.

However on the third day of his trial at Birmingham Crown Court he pleaded guilty to a charge of manslaughter by reason of provocation.

James Burbidge QC, prosecuting, said the plea was acceptable saying a stroke he had suffered before the attack had caused frontal lobe damage to his brain and may have affected him.

He said also taken into consideration was the prognosis for Mack's future health which was not good.

He added that the plea was being accepted as an "act of mercy'' and that it was not conceded that Mrs Mack had acted badly.

Judge Howard Morrison QC, said the case was a tragic one for everyone concerned and that medical reports suggested that Mack, who is suffering from prostate cancer, had no more than 18 months to live. He adjourned sentence to await the outcome of medical tests.

Detective Chief Inspector Adrian Pearson, the principal investigating officer, said afterwards: "I think it is the best outcome in all the circumstances. One has to bear in mind the age of Mack and the fact that this was an isolated incident.

''There was no history of domestic abuse and to all intents and purposes they were a happy and affluent couple. But notwithstanding that Mrs Mack met with a violent and completely unprovoked death. The injuries were shocking.''

''Quite what led Mack to act in the way he did remains largely a mystery but I am satisfied we have investigated this incident thoroughly and meticulously.''

He said Mack was a businessman and believed he had made his money by selling businesses. The couple had lived in a huge house in grounds which had five to six bedrooms and an outside pool.

Mr Pearson continued: "Mack admitted his guilt in full. The only thing he sought to minimise was that he said he could not remember how many times he had stabbed his wife.''

The officer said Mack had only admitted about six times when in fact there were many more, many of which were inflicted as she lay dead on the floor.

''It is quite chilling as his wife lay on the floor apparently dead he went back to bed," added Mr Pearson. ''He says he went to sleep and the following morning had breakfast in the same room, at one point moving her body to get milk from the fridge to put on his cereal.

''He was then able to go shopping and go to a dental appointment. He displayed absolutely no emotion at all.''

The court had heard the defendant and his wife who lived at Mockley Close, Gentleman's Lane, Ullenhall, near Henley-in-Arden and had presented themselves as a devoted couple although there were tensions in the marriage and in 2004 lawyers had been consulted about a divorce.

Mr Burbidge said Mack had rung the police on December 13 to report the stabbing and officers who arrived at their 1.8million home found Lorraine Mack's body in the kitchen, partially covered in a sheet.

When interviewed Mack claimed that in the early hours his wife had told him she wanted a divorce, that she could get 90 per cent of his pension and all of the house.

He said she had rushed at him holding a knife and that he had stabbed her to defend himself.

Mr Burbidge said after the killing Mack had gone to bed and the following day had gone about his normal daily business before phoning his sons and then the police.