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.

He told Sky News: “We’ve warned this could happen. This time three officers nearly lost their lives. What’s it going to take for the government to act?”

Mr Fairhurst called on the Ministry of Justice to ensure that no inmate in a separation centre has access to kitchen equipment or any items that could be used as weapons. He also reiterated calls for frontline officers to be issued with stab-proof vests without delay.

He explained: “These are dangerous individuals – terrorists, murderers, violent extremists – and staff are going into these units without adequate protection. It’s not acceptable.

“We’ve been told that stab vests look too intimidating. Frankly, that’s ridiculous. Our members’ safety must come first.”

The Justice Secretary has yet to respond publicly to the POA’s request for an urgent meeting.

Mr Fairhurst also warned the attack risked encouraging copycat assaults in other high-security prisons, and said prison intelligence teams needed to be given greater resources to identify and isolate dangerous individuals before they strike.

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: "Extensive enquiries continue to establish the full circumstances and explore any potential motivation.

"We are keeping an open mind as we investigate to establish the facts."

Durham Constabulary is supporting the probe.