As I drove home recently, my ear suddenly tuned into the car radio and, as I listened to the details of an inspection report, I found myself trying to work out which prison it was referring to.

The report revealed how “the worst possible conditions” had been found. Cells were vermin-infested and overcrowded, sewers and toilets were blocked, windows were missing, the few staff in charge were overwhelmed with work, physical attacks were at record levels, mentally ill prisoners were killing themselves and many others self-harming … so it went on.

What prison were they talking about?

Liverpool? Durham? Pentonville or Wandsworth?

The promise of an extra 2,500 officers doesn’t mean much when far too many of them leave soon after joining

It turned out that it wasn’t any of those. What I was listening to was a description of Bedlam mental hospital, well over a century ago. But it is no exaggeration to say that those who walked Bedlam’s landings would recognise many of the shocking conditions that can be found in today’s prisons.

Almost 68,000 people went to prison in England and Wales in 2016. In the same year, 344 people died in prison, 120 reaching such depths of despair that they chose to take their own lives rather than face the anguish of one more day. More than 8,000 of those released were recalled, there were 26,000 assaults (that’s 500 a week), riot teams were called out nearly 600 times, and there were more than 2,500 fires and 40,000 acts of self-harm.

For both prisoners and staff, our jails are less safe now than at any time since records began – with more self-inflicted deaths, self-harm and assaults than ever before. The report on HMP Liverpool last week by Peter Clarke, HM chief inspector of prisons, recorded the worst conditions inspectors had ever come across.

As tempting as it is to point to the need for more money and prison staff, the truth is that the real culprit is much closer to home. It’s Joe Public.

Despite the wealth of evidence to the contrary, the public view of prisons is still that they’re “holiday camps”. The longer the sentence and the harsher the regime, the better. Ask about deaths in custody and often the answer is: “Who cares?”

Who cares? Only a small minority. But we all should, and until that changes politicians have little incentive to improve things, despite the evidence that reoffending costs £15bn a year.

We desperately need an honest conversation – an independent inquiry into exactly what we want our prison system to deliver in terms of punishment, deterrence, rehabilitation, reducing reoffending and value for money.

Liverpool prison has 'worst conditions inspectors have seen' Read more

Once we have decided what we want the prison system to do, based on the evidence of what works, then we need to resource it to do exactly that.

What is certain is that we need more money – much more money. The prison service has lost almost a billion from its budgets since 2011, frontline staff numbers are down by almost 7,000, and the promise of an extra 2,500 officers doesn’t mean much when far too many of them leave soon after joining, once they realise what a dangerous and thankless task they have signed up for.

If we don’t act, a century from now our descendants will look back on the prisons of today with the same incredulity and horror that we feel about those Bedlams into which our great-grandparents tossed their damaged, deranged and disadvantaged.

• Mark Leech is the editor of The Prisons Handbook for England and Wales