'Life means life' legislation under fire
Ministers denied they had set themselves on a collision course with the judiciary by proposing a rigid system of "life means life" sentences and 30-year minimum terms for the most serious killers.
But critics accused Mr Blunkett of trying to tighten his grip "around the neck of the judiciary".
The tough new sentences came in the wake of a law lords ruling which said the Home Secretary's powers to decide how long dangerous criminals stay in jail breached human rights.
Mr Blunkett said anyone who abducts and murders a child should die in jail compared with the current practice of handing them a 20-year minimum sentence.
So-called "whole life" terms will also be imposed for terrorist murder or multiple murders which are premeditated, sexual or sadistic, and for murderers who have killed before.
Prisoners currently serving minimum terms fixed by the Home Secretary will have the right to ask a judge to look at their sentence again.
Mr Blunkett said: "These principles would ensure that for the most serious crimes, such as the sexual, sadistic murder of children, or terrorist murder, life should mean life, as opposed to current practice of a 20-year minimum term.
"For other serious crimes, such as the murder of a police or prison officer in the course of duty, or a race-motivated murder, a minimum term of 30 years' imprisonment should be passed, an increase of 10 years on current sentencing practice."
Mr Blunkett said judges had not proved capable of providing clear and consistent sentencing. The lack of clarity that exists now following the challenges to the previous powers make it necessary to sort this out," he told BBC Radio 4's Today programme.
"It will be parliament that decides the structure. It will be judges that act within it."
The Bar Council, representing barristers in England and Wales, said it opposed the changes. A spokesman said the plans were "constitutionally a leap in the dark".
"I think he [David Blunkett] is trying to institutionalise the grip of the executive around the neck of the judiciary, and that is not healthy for the long-term constitutional arrangements of the country," he said.
"By legislative creep, we will gradually erode the separation of powers, something which has for hundreds of years been seen to bea strength in our democracy."
Mark Littlewood, of the civil rights organisation Liberty, said: "Longer prison sentences may help the Home Secretary appear 'tough' but they will do nothing to reduce crime.
Sentences should not be determined by politicians who do not know the specifics of the "case and may be more interested in securing good headlines than in securing good justice."
