In 1943, as Britain emerged from the Second World War, something remarkable was happening in the justice system. Just 29.1% of offenders who left prison or completed community sentences went on to commit another crime within two years. It wasn't perfect, but it suggested the system had some grip on rehabilitation.

Fast forward eight decades. That figure now stands at 48.7%. Nearly half of everyone the justice system processes will be back committing crimes within 24 months. The failure rate has surged 67% since 1943.

The timeline tells a story of steady decline punctuated by sharp drops in effectiveness. Through the 1950s and 1960s, reoffending rates crept upwards but remained below 35%. The 1970s saw the first major spike, pushing past 40% for the first time. By the 1990s, that barrier had been smashed, with rates hitting the mid-40s.

What changed? The data spans decades of different approaches to criminal justice. The post-war consensus on rehabilitation gave way to tougher sentencing policies. Prison populations swelled. Community programmes were cut. Each shift in philosophy shows up in these numbers.

The 2000s brought some hope. Reoffending rates dipped slightly, suggesting that investment in rehabilitation programmes and resettlement support was working. But that progress proved temporary. The financial crisis and subsequent austerity measures coincided with rates climbing again.

The most troubling trend appears in recent years. The rate that held relatively stable through much of the 2010s has started climbing more steeply. Whatever gains were made in rehabilitation effectiveness have been lost.

This isn't just an academic exercise in criminal justice theory. Every percentage point increase represents thousands more victims of crime. It means families whose homes are burgled, businesses facing theft, communities dealing with antisocial behaviour. When the system fails to prevent reoffending, everyone pays the price.

The current rate means that for every 100 people released from prison or finishing community sentences, 49 will commit another offence serious enough to result in a conviction within two years. The justice system has become little better than a coin flip at preventing future crime.

Politicians love to talk tough on crime, promising longer sentences and more prison places. But this data suggests that approach has comprehensively failed. Eight decades of evidence shows that Britain has lost the ability to turn offenders into law-abiding citizens.

The question isn't whether the system is broken. The question is how long we'll keep pretending it works.