On 7 November 2018, Sudesh Amman pleaded guilty to six counts of possessing a document containing terrorist information and seven of disseminating a terrorist publication. On 17 December 2018, he was sentenced for those crimes. The judge reported that Amman’s ‘interest in Islamic extremism and Daesh appears to be more than just an immature fascination’; one of Amman’s notebooks, for example, recorded his ‘goals in life’, which included a desire to die a martyr.

Amman was sentenced to three years, four months’ detention. ‘You will,’ the judge said, ‘serve one half of that sentence in custody and then be released on licence for the remainder of it.’ On 23 January 2020, Amman was released from HMP Belmarsh. He was shot and killed by police in Streatham just over a week later, on 2 February: he had stabbed two people, both of whom survived the attack; a third was injured by broken glass, a result of the police shooting.

Speaking in the House of Commons the next day, the justice secretary, Robert Buckland, proposed ‘emergency legislation’ in response. Offenders like Amman will now, assuming the legislation passes, serve two-thirds of their sentence rather than half, and only be eligible for release then if the Parole Board deems them safe.

The Conservatives have been in power since 2010: if there is a flaw in the sentencing rules, it is their fault. (A raft of new counter-terrorism measures was introduced last year, for example, with no changes to the relevant laws; nothing was done, either, after the London Bridge attack in November, also carried out by a man released on licence after serving half his sentence.) Those rules aren’t the root problem, though. Amman, on the government’s proposal, would have been released a year or so later, just as eager to kill. More important is what happens after a sentence is passed, in prison and on probation.

The prison system is expensive: it cost £4.56 billion in 2018-19. Yet spending is down by 14 per cent in real terms since 2009-10. The latest report of HM Chief Inspector of Prisons for England and Wales says, apparently to reassure, that prisons are not ‘entirely in crisis’. But staff shortages were at times so acute that ‘risks to both prisoners and staff were often severe, and levels of all types of violence had soared.’ Access to rehabilitation services is limited, with 24 per cent of prisoners spending less than two hours a day outside their cells.

The probation service has yet to recover from Chris Grayling’s attempt, in 2014, to privatise it. By September 2018, the number of offenders being recalled to prison for breach of their licences was up by 48 per cent. In May 2019, the Public Accounts Committee found that reforms had wasted £467 million and ‘left the probation service underfunded, fragile’ and ‘in a worse position than they were in before the ministry embarked on its reforms’. The government proposes to return the probation service to public management, but it will take years to repair the damage.

There are no quick fixes to our contemporary estate. But sentencing reform is the Potemkin village of contemporary criminal justice policy: tinkering with early release conditions grabs a cheap headline, but the core structure remains rotten. The Ministry of Justice announced the proposed sentencing reforms by tweet, with ‘tough new approach’ in bold yellow capitals. What will the government say the next time – and there will be a next time – it has cause to put out an urgent statement following a terrorist attack?