We said it a week ago, before the situation escalated further: the overcrowding in English and Welsh prisons is unsafe. Since then Liz Truss, the Justice Secretary, has been to the House of Commons to try to suggest that the riot in HMP Birmingham was a one-off, and that a little more money will mean new prison places will be ready soon.

The disturbance in HMP Swaleside in Kent on Thursday night swiftly undermined her attempt to play down the simmering crisis. Of course, it is minimally reassuring that the Prison Service has protocols for dealing with disorder, and that it has “Tornado” teams that specialise in taking back control of prison wings from inmates, which they seem able to do successfully.

But good crisis management is no way to run a prison service.

There is a fundamental problem with prison policy in this country, which is that too many people are put in jail for non-violent crimes and that too little public money is spent on them, because they are never a priority.

We ought to spend more, but the more urgent priority is to imprison fewer people. That was the consensus this week espoused by the former deputy Prime Minister Nick Clegg, the former home secretaries Kenneth Clarke and Jacqui Smith, and the shadow Attorney General, Baroness Chakrabarti.

They are right, although it is worth asking why it did not happen when they were in charge, and it is worth asking Lady Chakrabarti what was the point of blaming Tony Blair, whose emphasis on being tough on the causes of crime is exactly what is needed now.

One of the problems, which Mr Blair at least understood, is the difficulty of securing public support for a more humane and effective policy. In order to do that, prison reformers need to make absolutely clear that people who are a danger to others will stay locked up. Once that is established they can make the case that prisons act as colleges of crime, turning petty criminals into hardened ones and, these days, turning rootless and directionless people into radicalised extremists.

Far from turning disordered and antisocial people into useful members of society, prisons make many social problems, including drug abuse, worse. Indeed, although crime has fallen in recent decades, prisons probably create more crime, by turning out more proficient criminals, than they prevent, by keeping other criminals off the streets.

One of the most promising things about Michael Gove’s brief tenure of the Justice brief was what he said, and the urgency with which he said it, about redemption. It must be possible for the criminal justice system to engage more constructively with the causes of crime – with mental health issues, drug addiction and social alienation – than the prison system does today.

Even at the most basic level, our prisons are failing. The rate of prison suicides, one of the less heralded success stories of the Labour government, has nearly doubled since 2010.

So, yes, let us pay prison officers more for doing some of the most difficult jobs in Britain, but let us also reduce the numbers of non-violent offenders sent to jail in the first place – not simply by cheap schemes for tagging, but by rigorous programmes of rehabilitation.