A POLICEMAN stabbed his wife almost 100 times after she taunted him about an affair she was having with a man nearly half his age.

PC Graham Jones, also known as Ivor, was said to have told his hairdresser wife, Maria: "If I cannot have you, I will kill you."

He later killed the 36-year-old by stabbing her in the bedroom of their £250,000 detached house in Ingleby Barwick, near Stockton, on December 2.

Yesterday, father-of-three Jones, 40, appeared in the dock at Teesside Crown Court where he pleaded not guilty to murder, but guilty to manslaughter on the grounds of diminished responsibility.

At an earlier magistrates' court hearing, details of which can now be published, it was revealed that Mrs Jones had formed a relationship with a 21-year-old after the marriage ran into difficulties.

Jones was suspicious, and when he challenged his slim, dark-haired wife, she admitted having an affair.

"She used to taunt him about his sexual powers compared to the 21-year-old," his solicitor, Craig Beer, told the earlier hearing.

The officer, who worked for Cleveland Police for 20 years and was based at force headquarters in Ladgate Lane, Middlesbrough, was prepared to forgive his wife, but she wanted an "open marriage".

The Crown Court was told that two medical experts, who had examined Jones, agreed that he was suffering from depression at the time of his wife's death.

Franz Muller, prosecuting, said: "Both firmly stated that at the material time his responsibility was substantially diminished as a result of that mental illness.

"There is an authenticated history of depression as far as the defendant is concerned, pre-dating these events."

Mr Muller said Jones claimed his wife had told him in the run up the killing: "You know I have slept with this man on a number of occasions. How are you going to put up with the fact that I am going to sleep with other people?"

Jones's father, Graham, a retired police officer, had died following a fall last September.

This followed the deaths of his mother and brother within months of each other, which was said to have put a strain on him and the marriage.

The couple had also faced a malicious charge that they had physically abused a child - only to see the case dropped on the day it was due to begin.

Mrs Jones later went to stay with her parents near Burton-upon-Trent, Staffordshire, which was where she was said to have started the relationship with the 21-year-old.

Mr Muller said that Jones had a conversation with his sister, Debbie Robinson, in which he told her he wanted to kill his wife, although she later retracted her statement and claimed he said he wanted to kill himself.

Mr Muller said the Crown had taken the view that Jones's plea was acceptable, even though they still did not fully accept as the truth his account of what had happened that night.

He said the judge must decide whether the attack was spontaneous or premeditated.

When police discovered his wife's body at their home in Barwick Close, Jones had been found slumped across it, having taken a number of sleeping tablets.

Aidan Marron, for Jones, said there was concern over elements of his family background and requested a pre-sentence report to be prepared.

The Recorder of Middlesbrough, Judge Peter Fox, adjourned the case, telling the defendant: "There remains a significant issue for me to decide, which is whether the killing of your wife was spontaneous and unplanned, or whether there was an element of premeditation.

"I shall hear the evidence about that and come to a decision and then, having heard submissions, sentence you."

Jones, a former pupil at Northfield Secondary School, in Billingham, is in the Hutton Unit at Middlesbrough's St Luke's Psychiatric Hospital. He was remanded in custody until his next appearance, on June 3, when he is due to be sentenced.