A former accountant who stabbed his wife 86 times faces a life sentence after being convicted of her murder.

David Lilburn, 45, said that a black shadow had ordered him to stab his wife, Ann, but a jury at the High Court in Glasgow dismissed his claim of mental illness and returned a unanimous guilty verdict.

Afterwards Mrs Lilburn's son, also called David, who was outside the court with her two other children, said: “Our mother, Ann Lilburn, was the kindest and most caring person you have ever known. She led a simple and ordinary life which was tragically and brutally taken from her. We can only hope that now justice has been served our whole family will be able to grieve properly.”

The jury was played a recording of a call to the emergency services in which Mrs Lilburn, 43, could be heard as she pleaded for her husband to stop attacking her. She screamed to the operator: “I'm dead.”

The couple's marriage appeared to be heading for divorce after Lilburn started an affair with Lynn McGuire, 43. Lilburn told the court that the affair led to the “complete destruction” of his loyal wife and that his children lost respect for him.

Despite this he continued to meet Ms McGuire, treating her to trips and meals in expensive restaurants.

Lilburn told the jury: “I did not want it to stop, this adventure. I was enjoying it. It was fantastic.”

Mrs Lilburn consulted lawyers about a divorce and Lilburn was told to leave the family home. This culminated in the attack on Mrs Lilburn at their home in Paisley, Renfrewshire, in the early hours of July 29 last year.

Lilburn, who had been celebrating his birthday with Ms McGuire, a divorcée, had gone to sleep in the marital bed despite it being agreed that he would use a spare room.

When his wife returned home a row started and Lilburn banged her head repeatedly against a door frame and the floor.

Mrs Lilburn managed to send a text message to the couple's 25-year-old son, saying: “Came home at 2.15. Lockd out the house. Then let in and assaultd.”

After she sent the message Lilburn used four knives to stab her 86 times in the head, chest and limbs.

Lilburn told detectives that he had no memory of the attack.

During the trial he admitted to killing his wife and said that a “black shadow” had told him to do it. He claimed that his mental health had been suffering before the attack.

Andrew Lamb QC, for Lilburn, asked the jury to convict him of the lesser charge of culpable homicide on the ground of diminished responsibility.

The court was told that in 2001 Lilburn retired from his job as a forensic accountant, citing problems with his mental health. He had bipolar disorder and schizo-affective disorder diagnosed and received £1 million from his insurance policies.

Witnesses who had seen Lilburn before the stabbing, including doctors and family, did not have any concerns about his mental health.

Derek Ogg, QC, for the prosecution, dismissed the black shadow claim as a “convenient excuse”. He told the jury: “He is clever enough, manipulative enough and has the intelligence to put together this latest get-out-of-jail-free card.”

Lilburn will be sentenced in September.

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