A Hackney Council meals on wheels worker was “decapitated” by her partner while still alive, the Old Bailey heard this afternoon.

And son Kirk was called to give evidence against his father, claiming Dempsey Nibbs was “really, really, really, really shocked” after Judith Nibbs told him she had sex with other men.

The elder Nibbs, 69, is alleged to have beheaded Judith, 60, at their home in the Charles Estate, Hoxton, on April 10, 2014. He then smashed up her head and flushed it down the toilet, prosecutors claim.

Concluding his opening statement this afternoon, prosecutor Crispin Aylett said: “At the point of decapitation, she had in fact been alive.

“The decapitation wounds were consistent with a bladed knife and there were several cuts to the skin. There were also a number of blunt injuries [bruising] consistent with gripping.

“Over a period of time, the defendant had threatened and behaved violently towards Judith. Unsurprisingly she had begun to fear for her own safety.

“There can be no doubt the defendant decapitated and then disposed of her head. By dispensing of the head, it indicates the contempt he felt for her at that time.”

Mr Aylett then called the defendant’s son, 30-year-old Kirk, to give evidence as his father, wearing a beanie hat and grey jumper, watched on.

Kirk Nibbs, who lived with his parents, said in April 2013 Judith had told him and his father she was going on holiday to France to see “friends”. In fact, photographs showed she had visited Morocco, though Judith didn’t deny this.

By the end of 2013, the younger man also recalled his mother speaking to other men on Skype in the house, and even introduced him to one, he added. In February 2014, the elder Nibbs began sleeping in the spare room, the couple’s son said.

On March 19, Judith went to Preston to visit family, he added. “My dad suspected she was seeing somebody else,” Mr Nibbs told the court.

The defendant wanted to check his wife’s computer, but didn’t know how to use it, it was said. Kirk Nibbs told the court he had checked on his father’s behalf, and was shocked to find she had taken “dirty photos of herself”.

“I didn’t expect that,” Mr Nibbs told the court. “I thought: ‘Oh my gosh, I can’t believe my mum would do this.’”

He added he had downloaded the images to a pen drive under the title of “mum slut”, as evidence for his father in meetings with a solicitor.

Events culminated on April 7, when Judith admitted sleeping with other men during a row with the defendant, it was said.

Their son told the court: “I heard my mum say she had sex eight times. That was the first I was aware. My dad was really, really, really, really shocked. He was really hurt about what she did.”

Nibbs Snr admits killing Judith Nibbs, but claims he did so in self-defence. He denies murder and obstructing the coroner from holding an inquest by disposing of her decapitated head.

The trial continues.