Murderer Paul Robson should still have been behind bars when he killed his teacher ex-partner in a jealous rage.

The cage fighting coach had been unlawfully at large, wanted on a prison recall for breaching the terms of his licence, for 20 months when he sneaked up to Caroline Kayll’s home in Linton, Northumberland

It was on that night in November 2020 that he used his mixed martial arts skills to brutally attack the 47-year-old and the 15-year-old boy with whom she had started an illicit sexual relationship.

Ex-con Robson had spent lengthy spells of his life in jail and has 21 convictions for 92 offences over more than 30 years on his record.

He was sentenced to 10 years for drugs and firearms offences in 2014, and while at HMP Northumberland he gained “trusted” status and worked in the education department, where Mrs Kayll was then a teacher.

He was released on licence in November 2018, but was then recalled to prison in March 2019 because he had breached his licence, and from then on was unlawfully at large.

Newcastle Crown Court was shown two photos of the 50-year-old defendant with fellow fighters in a gym.

Robson tried to downplay his skills, saying he had only fought in a cage on two occasions around 10 years ago, claiming he was too old to get in the ring now.

But the jury was shown a flavour of his real demeanour in a video captured by a police officer’s body-worn camera.

Officers from Northumbria Police had travelled to Scotland to collect him after he was arrested in Glasgow and the video showed Robson angrily demanding to have his glasses back.

When it was explained they were needed for evidential purposes, Robson shouted to the police, saying: “Don’t think I’m some sort of mug, I have been here before.”

He went on to warn the police he would put hands on them if they laid hands on him, and demanded to speak to the sergeant before finally agreeing to be cuffed.