A man who tried to claim his partner had suddenly “gone limp” during sex has been jailed for at least 18 years for her murder.

Robert Simpson-Scott, 44, strangled 55-year-old Sally Cavender on December 4 last year following a drunken row at his home in Lamb Drove, Cambourne, Cambridgeshire.

In a 999 call made at 11pm that evening, Simpson-Scott said: “She’s dead, she’s gone, I’ve killed my wife,” but he was not arrested immediately.

She was rushed to Addenbrooke’s Hospital with a fractured spine, multiple rib fractures, hypoxia brain injury and bruising to her face, neck and arms, but Simpson-Scott was only arrested when doctors raised their concerns with police.

He was detained on suspicion of attempted murder at around 3am on December 5, and told police she had lost consciousness during sex.

Cavender, who lived in Sawston, died about two hours later at 5.30am – a few days before her mother, who had to be told on her death bed that her daughter had been murdered.

His trial at Cambridge Crown Court heard the couple had been in a relationship for about 15 years and both had alcohol problems.

It is believed they had been arguing about Cavender’s drinking on the night she died after Simpson-Scott cut his foot on a smashed wine glass.

He admitted denied murder but admitted manslaughter, claiming to have lost his memory of the incident, but the jury rejected his defence and he was found guilty of murder on June 24.

Jailing him for life at the Old Bailey on Thursday, Mrs Justice Cheema-Grubb said: “The jury was sure you strangled Ms Cavender intending to kill her or cause her really serious bodily harm.

“You acted with an intention to kill – it was no doubt a short-lived intention and you panicked when you realised you really had killed her, but there can be no mitigation in your case of a lack of intention.

“You’ve robbed Sally’s family of a beloved child, sister and auntie. You killed her at a time when you knew her own mother was dying and had to be told of her first-born daughter’s death while she was on her death bed.”

Justice Cheema-Grubb said Cavender’s injuries indicated she would have been struggling until the moment she lost consciousness, adding: “She would have known she was being strangled to death by someone she loved. It was a terrible way to die.”

Anthony Metzer QC, for Simpson-Scott, said the attack was an “isolated incident” and had not taken place in a context of domestic violence.

Metzer said: “He’s experienced some tragedy in his personal life – his father died subsequent to his arrest and (the court) may know of his attempted suicide before his trial.

“People are complicated, even people convicted of murder, and nobody but the defendant knows what happened on that night.

“But he will have to live with the fact he killed his long term partner – murdered his partner – but he loved her and he will retain the guilt for having taken her life.

“He’s acted in the most terrible way and brought about this tragedy himself.”

In a statement, Cavender’s brother Nick Cavender said: “Sally was a bright and bubbly person but she also lacked self-confidence and battled with alcohol dependency for many years.

“While that led her to make very poor decisions about her lifestyle and choice of partner, she was a very vulnerable person and no-one deserves to have their life ended in the way that hers was.

“Mum did everything she could to support Sally, and while as a family we wish we could have done more to help her, the reality was she was being controlled and used by an evil, manipulative man who did nothing to help her.”

His sister Suzy said: “We are deeply traumatised by Sally’s tragic murder and were too shocked and overwhelmed with grief to be able to attend the trial.

“It is sickening that Robert tried to twist Sally’s murder and it has only added further injury to our shock and pain.”