A former prison governor and expert on extremism has said the brother of the Manchester bomber should be put into isolation after he attacked prison officers last weekend. Ian Acheson made the claims following an incident where Hashem Abedi attacked officers at HMP Frankland.

Abedi, 28, is serving a 55-year sentence for assisting his brother’s suicide attack on Manchester Arena which killed 22 people. Last weekend, he left three prison officers in hospital after an unprovoked attack. He threw hot cooking oil over officers before stabbing them with “homemade weapons”.

Acheson, a former prison governor who carried out a review of Islamist extremism in jails in 2016, described Hashem Abedi, 28, as the second most dangerous prisoner in the UK after the serial killer Robert Maudsley. The families of five Manchester Arena victims wrote to Shabana Mahmood, the justice secretary, to express their “absolute disbelief” that Abedi was able to carry out the assault in prison, reports The Times.

Acheson said Abedi should be totally isolated: “We don’t have the death penalty so the only other alternative is extreme custody — if it turns him mad then so be it.”

He added: “If extreme custody and total isolation is the price to pay for protecting national security and protecting staff who have to manage this risk, then so be it.

“This is a moment of crisis of control given Abedi’s background. There are so many catastrophic incidents happening.”

Concerns have been raised as to why Abedi was not placed in a close supervision centre - reserved for the most violent prisoners. Abedi was living in a separation centre, reserved for extremists in order to prevent them radicalising other inmates but this means he had more entitlements than those in close supervision centres.

Crucially, he had access to a kitchen which is believed to be where he found some items for the attack.

Prime Minister Sir Keir Starmer said he was “appalled” by the attack and announced a ban on dangerous inmates using kitchens.

Articles three and eight of the European Convention on Human Rights have prevented officials from placing certain prisoners in close supervision cells. This is because the articles protect against “inhumane” treatment and the “right to respect for family and private life, home and correspondence."

A letter from the Manchester victims families, reported by the BBC, read: “We are writing in absolute disbelief [that the] evil Hashem Abedi has been allowed to cause danger to life.

“As the families of Megan Hurley, Eilidh MacLeod, Chloe Rutherford, Liam Curry and Kelly Brewster, our beautiful, beloved children who were so tragically murdered along with 16 others in the Manchester Arena terror attack in May 2017, we find this situation beyond comprehension.”

The families added: “In our view, he should not be allowed any privileges whatsoever while serving a sentence for the deaths of 22 innocent lives and the injuring of many more.

“He should not have access to anything that he can weaponise, such as hot oil or items he can turn into blades.”

Abedi is understood to have made two 20cm knives out of cooking trays and wrapped kitchen towels around them for handles.

The Ministry of Justice has said there will be a full, independent review into the incident begun by the end of the week.

Abedi aided his brother, Salman Abedi, to carry out the Manchester Arena attack on 22 May 2017, in a large foyer filled with people after an Ariana Grande concert.

The attacker emerged from a stairway, crossed the concourse and detonated his device - 22 people died in the incident.