By a perverse coincidence, on the same day as the two policewomen were brutally murdered at Tameside near Manchester the ECHR in Strasbourg ruled that indeterminate sentences for the protection of the public (known as IPPs) were ‘arbitrary and unlawful’.

It raises the question of what action should be taken to deal with Dale Cregan, if he is found guilty of the killing of the two police officers and perhaps also of complicity in two other killings earlier in the year – a father and son, both with a violent history. With two violent families and a simmering gang warfare imposing a reign of terror in certain Manchester neighbourhoods, at what point is it safe, after an atrocity such as that just perpetrated on Tameside, to release back into the community after a given prison sentence violent criminals who show no sign of remorse?

According to the Ministry of Justice there are now 6,078 prisoners serving IPPs, including 3,531 who have already served a longer sentence than that set down by their trial judge. This issue however is confounded by the fact that the 2005 Act which introduced IPPs required that rehabilitative treatment should be made available, but in most cases it has not been or not on the scale expected or too delayed. Clearly what is needed therefore is much greater emphasis and resources being applied to rehabilitation, not only of course to the most violent offenders but to all who might gain from intensive treatment of this kind.

The Home Office however plans to replace IPPs by a new ‘extended determinate sentence’. In other words dangerous offenders will simply be locked up longer – back, under the new hardliner Grayling as Justice Secretary, to Michael Howard’s ‘prison works’ and perhaps even to the old, discredited doctrine of preventive detention. But while society does have to be protected from very violent criminals, warehousing them indefinitely in prison is not the answer, as the ECHR is now insisting.

It is a very difficult lesson to draw at a time of prolonged austerity, but the only way to reduce the appalling crimes of a tiny section of the population is to focus far greater efforts on rehabilitative programmes, both in prison and by compulsory attendance at secure units outside in the community.

Even more important is a major campaign, piloted by projects in key areas throughout the country, systematically to tackle the skein of interconnected income, employment, housing, education and family problems in the early years of life from which so much serious crime later derives – though getting agreenment to that in the current political climate is probably next to impossible.