A former RAF serviceman who smothered his 76-year-old mother to death with a pillow has been jailed for four years and eight months.
Thomson told police he had woken up and decided to kill his mother
David Thomson, 49, acted as a carer to mother Elizabeth who regularly mocked him, the High Court in Edinburgh heard.
Thomson waited until she went to bed before holding a pillow over her face, struggling with her until she died.
Thomson, who was originally charged with murder, had earlier admitted the reduced offence of culpable homicide.
The court was told Thomson was worried the family home would be repossessed as his debts spiralled to £60,000. He had made a suicide bid weeks before the killing, but his mother told him he was a failure who could not even kill himself properly.
When Mrs Thomson went to bed on 14 January, her son attacked her with the pillow. Thomson overpowered her as she struggled with him, causing her to also suffer bone fractures in the attack.
Passing sentence, Lady Smith told Thomson: "On 14 January this year your mother went to bed as usual in her own home where she was entitled to assume she was safe and free from harm.
"The last thing she should have had to fear was that she was at risk from her own son.
"She was entitled to assume that after her night's sleep she would get up in the morning and carry on with her life as usual. That was not to be the case."
Lady Smith said Thomson had kept on applying pressure to her face until he were sure she was dead, adding: "These were conscious and deliberate acts."
"This was a terrible event. Any right-thinking member of society would be appalled."
The fatal attack took place at the family home in Avonspark Street, Glasgow.
Lady Smith said she took into account that Thomson was "effectively a first offender" and that he had been suffering from depression.
She also said that his mother had not been supportive following his suicide bid.
But Lady Smith said none of this could excuse Thomson's actions over the killing of his mother and told him he would have faced a seven-year jail sentence for the crime, but for his guilty plea.
Lady Smith pointed out that Thomson had been assessed as posing a very high risk of offending within the community. She ordered that he should be supervised for a further three years at the end of his custodial sentence. Defence counsel Louise Arrol said an "extremely unusual" background lay behind the offence.
Cup of coffee
She said: "He had difficulty dealing with his relationship with his mother. He felt she was someone who would mock him regularly.
"He is somebody who has had a relatively unremarkable life. It is a tragedy for all parties."
Thomson served in the RAF until 1990 and then went into the ambulance service before becoming his mother's sole carer.
He cooked, cleaned and looked after her, but said she subjected him to verbal and psychological abuse. He only went out to the shops.
After the attack he returned to his room and changed into fresh clothes and made a cup of coffee before dialling 999.
He told the emergency operator he had just killed his mother and added it had been mounting up for years.
He later told police: "I woke up and just decided to do it."