The Law Society has criticised plans to extend mandatory life sentences, telling the government to trust judges’ discretion. The new regime, which would replace the indeterminate sentencing system with long determinate prison terms and mandatory life sentences for anyone convicted of a second serious sexual or violent crime, was announced last week by justice secretary Kenneth Clarke.

Clarke said: ‘The new regime will restore clarity, coherence and common sense to sentencing, rid us of the inconsistent and confusing [indeterminate public protection] regime and give victims a clearer understanding of how long offenders will actually serve in prison.’

But the Law Society warned that the measures will erode the sentencing judge’s discretion to impose the most appropriate penalty. Chief executive Desmond Hudson said: ‘Judges should be trusted to exercise their discretion when sentencing offenders, taking into account sentencing guidelines and the maximum penalty laid down by parliament.’

The chair of the Society’s criminal law committee Richard Atkinson said: ‘Anything that fetters the discretion of judges is bad news for justice. It takes away the opportunity to match a sentence to the specific circumstances of a case, which can lead to poor decisions.’

Atkinson warned that the changes would lead to more people going to prison - and more violence as suspects will be keener to evade arrest.