The scale of the challenge facing Prime Minister Keir Starmer's new government is writ large in Britain's prisons, which are within weeks of being too full to accept new inmates, leaving the government with unpalatable and costly choices.

Britain has western Europe's highest rate of incarceration, according to the World Prison Brief database, and faces a crisis after a new building program failed to keep track with tougher sentencing laws that have fueled a growing prison population.

Already, many prisons are housing two inmates in cells built for one, and emergency measures triggered by the previous Conservative government mean some offenders have been released early and court cases delayed to avoid new arrivals.

The head of the body representing prison governors has warned that unless a solution can be found, offenders will soon have to be held in police cells, constraining officers and disrupting the wider judicial system.

Labor leader Starmer has described the state of Britain's prisons as a "monumental failure" of the last government, but like other challenges – from sewage in rivers to strikes at the National Health Service – that stance may only hold for so long.

He also has little financial room to maneuver. According to the Institute for Government (IfG) think tank, spending on prisons is set to fall by 5.9 percent each year relative to demand over the coming years.

Tom Wheatley, president of the Prison Governors Association, said the new government had no time to waste.

"I think they can (act quickly enough), but only just. It's going to be touch and go," he told Reuters.

"We're nearing the line on what can be safely accommodated, even in overcrowded conditions."

High imprisonment rates

As of July 5, England and Wales had 87,453 prisoners, up from 86,035 a year earlier and within a whisker of what prison governors see as a maximum capacity of 88,864.

That equates to around 144 prisoners per 100,000 in the population. Imprisonment rates are around 25% lower in France, Spain and Italy and less than half in Germany and the Netherlands. The United States, however, has a far higher rate at 531 prisoners per 100,000.

Options to tackle overcrowding include releasing more offenders with electronic tags or giving people suspended sentences, meaning they would only be jailed if they were to reoffend again within a certain timeframe.

Starmer has promised to get to grips with the problem but warned it would take time. "We can't fix it overnight. Therefore, it is impossible to say we will stop the early release of prisoners," he said in his first press conference after his party won a landslide victory in last week's election.

Starmer was previously the chief prosecutor for England and Wales, and his longer-term thinking may be detected by his choice of new prisons minister: businessman James Timpson, whose shoe-repair and key-cutting firm employs ex-offenders and who is known for his belief in rehabilitation.

Britain's Ministry of Justice said a third of former prisoners were proven to have committed another offense within 12 months of release, rising to more than half of those who had served less than a year behind bars.

Any attempt to improve that would take time and money.