Parliament Fills the Prisons. A Formula Empties Them.

On the day the machine finally spoke, there were 212 places left in the adult male prison estate. Not 212 cells — 212 places, the last inches of headroom in a system built for roughly 80,000 souls and holding close to 86,000. At that point the escalation procedure ran as designed: the Ministry of Justice's Permanent Secretary wrote to the National Security Adviser, the Lord Chancellor wrote to the Prime Minister asking for authority to release prisoners eighteen days early, and the paperwork noted, with admirable understatement, that "any delay would significantly increase risk, including the risk of release in error." Nobody in that chain had stood for anything. The last elected fingerprint on the file belonged to whoever passed the sentencing law that filled the cells in the first place, years earlier, for a different reason entirely.

That chain did not appear from nowhere. In October 2022, HMPPS leadership, with the agreement of its Board, set three "operational red lines": prison staffing must not fall below 80 per cent of target; 1,500 places must always be held out of use for maintenance; and "contingency crowding is capped at the maximum viable level, set by HMPPS." Ministers agreed to these limits and, to date, have not crossed them. Notice the architecture of that sentence. The ceiling on how crowded a British prison is allowed to become was drawn by the organisation that runs the prisons, and the maximum viable level was set by the same body whose job it is to live inside it. Ministers signed off on a number that officials had already chosen.

This is not corruption. It is worse than that, in the way these things usually are: it is sensible. You cannot run a seven-day national capacity crisis by referendum, and nobody serious wants Parliament voting weekly on cell counts. The case for delegating operational thresholds to people who understand staffing ratios and maintenance backlogs is not a bad one, and it is the case the Ministry of Justice would give you, more or less verbatim, if you asked. Dame Anne Owers, in her Independent Review of Prison Capacity, called the 2022–24 crisis a "conjunction of some specific circumstances" layered on a longer structural problem — sentence inflation meeting the expense of building anything to hold the result. That is a fair description of the mechanics. It says nothing about who is answerable for them.

Because the mechanics only exist to manage a population that politicians created on purpose. The Howard League's reading of the numbers is blunt: this is not a response to rising crime, which has fallen, but to sentencing policy — sentences handed down more often and for longer, frequently in response to campaigns calling for new offences or harsher terms. Every one of those campaigns has a name attached and a press release to go with it. When a minister stands up and promises longer sentences for a category of offence, the credit is collected in full and in public. When the resulting overcrowding forces an early release scheme eighteen months later, the decision is processed by letter between officials and dressed as an operational inevitability nobody chose.

The results of that asymmetry are on the record. Between October 2023 and September 2024, some 13,325 people were released early under the End of Custody Supervised Licence scheme. When that stopped being enough, the government introduced SDS40, cutting the proportion of a standard sentence actually served in custody from 50 per cent to 40 per cent — a change to how long a criminal sentence means, in practice, administered without a parallel debate about what sentence lengths were for. Shabana Mahmood, the Lord Chancellor at the time, described it as the only way to "avert disaster." That is an honest sentence, and also a confession: the decision had already been taken, by arithmetic, and her job was to ratify the emergency it produced.

Here is the sentence I'll allow myself: a state that lets politicians take full credit for filling prisons and no blame for emptying them has not solved the accountability problem, it has laundered it through a spreadsheet.

Attlee's government inherited a country that was bankrupt and rationed and still found the nerve to build 200,000 houses a year because someone had decided to, and knew he would answer for the number. The prison estate has had no equivalent decision — no minister has stood at a despatch box and said "we will build this many places, by this date, and if we fail, sack me." What it has instead is a red line set by the people who staff the cells, a trigger set by the people who count them, and a Prime Minister who finds out the system is full by letter, at which point the only remaining choice is which category of prisoner gets to leave early.

The row this summer over prisoner releases will not be the last of its kind, because nothing about the structure that produced it has changed. Sentencing will remain a campaign tool. Capacity will remain a formula. And the next time the count reaches 212, or fewer, the letter will go out again — signed, as ever, by nobody the public can remove.