Manchester Arena terrorist Hashem Abedi was “silent and grinning” before he stabbed and scalded three prison officers in a planned attack at HMP Frankland, with a chilling picture showing the moments after the attack. The 28-year-old is understood to have melted down sachets of butter to hurl boiling fat at a female officer before stabbing two male colleagues with improvised blades fashioned from cooking trays, with a picture showing him grinning seconds earlier.

The incident happened in the kitchen of the prison’s separation unit, which houses Islamist extremists. One officer was slashed in the neck, and another was stabbed five times in the back, suffering a punctured lung. A source told The Sun: “There is no doubt he wanted to kill, and it is miraculous they all survived. But he was acting like a silent assassin.”

The female officer, who is in her 30s, was discharged from the hospital later that day. The two men, aged in their 30s and 60s respectively, were treated for life-threatening injuries but are now in stable condition.

Abedi, serving at least 55 years for helping his brother Salman plan the 2017 bombing, which killed 22 people, is believed to have acted with the support of other inmates. The insider added: “Abedi acted alone but probably colluded with others."

After the attack, a riot team restrained him. Abedi has now been transferred to HMP Full Sutton near York.

Mark Fairhurst of the Prison Officers’ Association has demanded that extremist inmates lose access to kitchens entirely.

A Ministry of Justice spokesperson said: “There will be a full review into how this attack was able to happen, alongside the police inquiry.”

Counter-terror police confirmed their investigation is ongoing. A spokesperson said: “We are keeping an open mind as we investigate to establish the facts."