Lord Woolf, the most senior judge in England and Wales, launched an attack last night on the Government's "extraordinary" stance on sentencing reforms.
The Lord Chief Justice opened a fresh rift with David Blunkett when he criticised the Home Secretary's plans to introduce a rigid system of mandatory sentences for convicted murderers.
Speaking in the second reading of the Criminal Justice Bill, Lord Woolf said the proposed rules failed to recognise the variety of different circumstances in murder cases.
He said the plans "indicate the problems that arise when sentencing becomes the subject of political interest".
He added: "The provisions are bespattered with requirements as to what a judge 'must' do. Some of the clauses provide a degree of discretion to the trial judge, but this is by no means always the case."
However, Mr Blunkett defended his proposals in a statement issued last night and revealed he was resigned to "agreeing to disagree" with Lord Woolf on various aspects of the controversial proposals.
"I want to make it clear that I firmly believe in the independence of the judiciary," he said. "It is their job to interpret laws and protect freedoms.
"However, I also firmly believe that we need, and the public expects, a clear framework that sets minimum terms for imprisonment for murder. In my view, these should be set out in statute, agreed by Parliament." He added: "The Lord Chief Justice and I have agreed to disagree on certain features of the Criminal Justice Bill. We are, however, united in our aim of improving the criminal justice system.
"As Home Secretary. I have no interest in being involved in appointment and would object to any politicisation of the judiciary. I am only interested in seeing a judicial system that is objective, consistent and transparent and capable of building public confidence."
The Government also faced anger over moves to limit the right to trial by jury in complex fraud prosecutions and in cases where there was a risk of "jury nobbling". Lord Falconer of Thoroton, the new Lord Chancellor, insisted that jury trials would continue to be the norm for the majority of cases. He told peers: "There is no intention of a full-scale assault on trial by jury - far from it."
Lord Brennan, a High Court judge and Labour peer, complained that the automatic right of trial by jury was driven by practical convenience rather than principle. He said: "In this country we have, it is said and I believe it to be so, a participatory democracy. Other than voting and paying our taxes, the only occasion on which we as citizens participate in a democracy is in a jury."
He added: "They command the confidence of their fellow citizens. They are independent of the state, and lastly, in my experience, as 12 good people and true they seek to exercise in a fair way their community common sense. What is wrong with this system?"
Lord Harris of Haringey, a Labour peer, told the Lords: "The changes before us today will go a long way towards restoring public confidence in the criminal justice system."Reuse content