His killer had roughed him up with a blunt object and shot him in the chest with a rifle before making off from the scene.

Police made the grim late night discovery after Mr Torrance was reported missing and their grisly find resulted in his 28-year-old widow Christina Torrance — known as Betty — and her lover David Watt being charged with his murder.

Their 1974 trial at Glasgow High Court made front page news as allegations of secret sex sessions, adulterous relationships and spurned lovers were made public in all their sordid glory in front of a 15 person jury.

Prosecutors claimed Hardgate man Watt had been the one who pulled the trigger but argued that Betty had been “just as sinister” and had played the role of instigator in the shooting and supplied the bullet.

Mrs Torrance was eventually cleared of any wrongdoing and left the dock in tears while Watt was convicted of murder.

Stephen Doyle, who was an 18-year-old police cadet at the time, had a unique perspective of the trial after being posted there by his superiors in order to watch the proceedings and help the cops who were stationed there.

He says the role also allowed him the opportunity to speak with Mr Torrance’s wife as she sat in her cell and has alleged that she joked with those around her about spending the night with a policeman if she was cleared of murder.

He told the Post: “That particular case was a particularly lurid and horrific case at the time.

“I have looked for the case over the last few years as it was always something that stuck in my mind.” “At lunch time and break time we would escort the prisoners back to the cells with the genuine officers.

“On one of these particular days about half way through the trial we were taking Christina Torrance back to the cell for lunch and one officer said if you get away with this I want a drink with you. She said ‘If I get away with this you can have the whole night with me’. That raised quite a laugh.” William Torrance’s murder trial heard that his body had been found at his 300 acre dairy farm on August 3, 1974.

His wife Christina had been the first person to raise the alarm and told police that her husband had gone missing after setting off to collect money for his dairy round the day before.

Jurors heard that the couple did not enjoy a happy marriage and that Mr Torrance had been having an affair with 26-year-old Dalmuir schoolteacher Jean McKenzie Orr while his wife had boasted of relationships with other men.

In evidence, Miss Orr admitted to having sex with Mr Torrance in his car, in the house and in the bathroom and said that Mrs Torrance had learned of their relationship after finding a diary she had left in the house.

She also said that Mrs Torrance had told her she would have stabbed her husband if there had been a knife handy on some occasions when they were arguing.

Another witness, Stuart Christie, said in the weeks after her husband’s death Betty had told him “I am glad the bastard is dead”.

Heather Pinkerton, whose husband Alastair was friends with Watt, claimed Mrs Torrance had told her that on the night her husband died she had been with her lover David Watt at the farmhouse.

She said Mrs Torrance told her that Watt had then left the house with a gun to go outside and wait for her husband.

Mrs Pinkerton also told the court that after her husband’s death Mrs Torrance had wanted to find out what Watt had said in his statement to police in order make her statement coincide with his.

Watt initially told cops he shot Mr Torrance in a struggle which he claimed was a “him or me” situation after going up to the farm in order to teach him a lesson and frighten him off.

He also took detectives to the foreshore at Loch Long where he said he had burned clothes and the site at Loch Lomond where he said he had thrown the gun in the water.

But in court he changed his story and claimed he had made up the confession because of his love for Mrs Torrance.

He went on to tell jurors that the reality was he had only become involved in the situation after he received a phone call from Mrs Torrance on the night of August 2 in which she said: “I am in terrible trouble. I have shot Billy and killed him.” A letter, which was written by Watt in prison and read out in court also revealed he had said: “I am not letting Betty away with it and keeping my fingers crossed. I have incriminated myself so much I don’t know if I have a chance.” He added: “Betty hasn’t a hope in hell. She is in for a shock.” However, the jury of four women and 11 men cleared Mrs Torrance of any wrongdoing and returned a not proven verdict.

Watt was convicted of murder and sentenced to life imprisonment.