CEP Senior Advisor Ian Acheson writes: "Shawcross has now disagreed publicly. The Home Office had, he said, ‘ignored’ key recommendations to beef up Prevent’s performance and the glass remained only ‘half full.’ I have some experience of bureaucratic sleight of hand at work when it comes to reviews and recommendations. When I was tasked by the Government to look into the Prison Service’s colossal and unforgivable failures in containing Islamist extremism a few years ago, I made 69 recommendations which were mysteriously repurposed into 11 without my consent; eight were finally accepted."

Hashem Abedi, 28, inflicted "life-threatening" injuries on the officers at HMP Frankland in County Durham on Saturday. He is being held at the jail for his role in the deadly bombings eight years ago and his latest attack has outraged many, including former prison governor Ian Acheson. Mr Acheson, who carried out a review of Islamist extremism in jails in 2016, called Abedi "the second most dangerous prisoner in the UK" and claimed he should be left in total isolation because "we don’t have the death penalty". "The only other alternative is extreme custody - if it turns him mad then so be it," he told the Times.

The threat of violence has never been far away from crowded jails but the problem is now endemic. The rehabilitation of offenders cannot happen within an unstable system. As the former prison governor Ian Acheson says: “Broken staff cannot help fix broken people.” A key factor in the crisis of authority in UK jails has been the rise of Islamist gangs after the jailing of radicals for terrorist attacks and plots. Almost 16,000 inmates in England and Wales now ­identify themselves as Muslim after a 190 per cent rise in their numbers in 22 years due to sentencing and religious conversions behind bars. Almost a decade ago, Mr Acheson warned the Commons justice committee that “all the ingredients for radicalisation” in jails were present. Islamist gang culture, sometimes expressed in loyalty to the Muslim Brotherhood, mixes with ordinary criminality. Conversion to Islam behind bars is driven partly by the protection offered by gang membership in increasingly anarchic settings.