A committee of MPs has warned that the criminal justice system is ‘facing a crisis of sustainability’ as government spending on prisons takes resources away from other aspects of criminal justice.

The Justice Committee said the government should make ‘radical moves’ to shift resources away from incarceration towards rehabilitation and projects that tackle the underlying causes of offending like social exclusion, poor education and drug addiction.

The call was backed by Law Society legal aid manager Richard Miller, who said that a reduction in spending on prisons would leave more cash for the legal aid budget.

The report - Cutting crime: the case for justice reinvested – is the culmination of two years’ research by the committee, which concludes that prison is an ‘expensive’ and ‘relatively ineffective’ way of reducing crime.

Establishing a financially sustainable sentencing framework, greater judicial involvement with local criminal justice boards and the setting up of a body to assess the effectiveness of criminal justice interventions are among the committee’s suggestions.

Committee chairman Sir Alan Beith, said: ‘Whoever forms the next government, they face a choice between unsustainable "business-as-usual" in the criminal justice system, and making some radical decisions.’

‘A demand-led policy of building ever more prison places is being fuelled by political and media pressure for more and longer custodial sentences, diverting resources away from measures which are more likely to prevent future crime,’ he said.

He added: ‘In an election year it is vital that there is a responsible debate about how we can use limited resources to cut crime, not a competition as to who will promise the longest prison sentences.’

Miller added: ‘Legal aid spending is the inevitable consequence of many of the other decisions made in the criminal justice system. So if a less penal approach was taken, that meant fewer people were imprisoned, it would generate savings for the legal aid budget, which would be a win-win situation.’

However, a Ministry of Justice spokesman said the government’s approach was working. ‘Since 1997 overall crime has fallen by 36%, violent crime has fallen even faster and the risk of being a victim is at its lowest for a generation. People who commit serious offences are going to prison for longer and are being rehabilitated — and the rate of re-offending continues to fall.’

Rodney Warren, director of the Criminal Law Solicitors Association, said the lack of government focus on alternatives to custody was unfortunate. 'One of the greatest strengths of an effective criminal justice system is that in the vast majority of cases, especially in the magistrates' court there are opportunities for diversion.

'We regret that there hasn't been a greater understanding of these opportunities and of how defence solicitors can play an effective role in helping their clients, which would reduce long-term cost to the criminal justice system.'