Mosley and Mairead Philpott were also convicted of six counts of manslaughter and sentenced to 17 years by Mrs Justice Kate Thirlwall KC. All three were found responsible for the deaths of Duwayne Philpott, 13, Jade, 10, John, nine, Jack, eight, Jessie, six and Jayden, five.

Philpott, who had a had called on his wife and Mosley to help him light the fire at the family home in Victory Road.

A source told The Sun in March this year that Philpott was “battered”, “bruised” and “in a bad way” after the prison attack at HMP Wakefield in West Yorkshire.

The unnamed source claimed another lag had pounced on Philpott from behind while he was on a landing, but prison guards rushed in to break it up. Philpott was said to have felt very sorry for himself afterwards.

While the killer remains in jail, Mairead Philpott and Mosley were both released. Mairead Philpott was sentenced to 17 years and was released in 2020 having served half of her sentence.

Mosley was released from HMP Durham on licence in January last year, according to the Ministry of Justice.

Hampshire Police confirmed a 58-year-old man died on Saturday at a property in Portsmouth, Hampshire. The force said his next of kin have been told and a file will be prepared for the coroner.

Philpott had hatched the arson plot, aiming to frame his former partner for the attack. But the gamble backfired as the house exploded in a huge fireball.