In a written Parliamentary answer, Mr Blunkett said the "heinous" nature of Shipman's crimes meant only a "whole life tariff" was appropriate.

These were the most heinous of offences and the grossest breach of the duty of trust he owed as a doctor to the victims, all of whom were trusting patients.

David Blunkett

The GP from Hyde, Greater Manchester, was jailed for life in January 2000 for the murder of 15 of his patients.

He joins a small group of criminals - including Rose West, Dennis Nilsen, Jeremy Bamber and the 'Black Panther' Donald Neilson - who have been told they will die in jail.

Mr Blunkett's decision means that Shipman, 55, is likely to die behind bars.

The announcement comes shortly before Dame Janet Smith, the senior judge chairing the public inquiry into the Shipman killings, is due to publish her initial report.

It is expected to say how many of the former GP's patients were murdered - there are some estimates of 297 victims, most injected with diamorphine.

Family anguish

Mr Blunkett wrote: "I do not usually comment on the tariff decided in individual life sentence prisoner cases.

"However I recognise that Harold Shipman's crimes raise issues of particular public concern and I therefore intend to depart from my usual practice in this case.

"I extend my deepest sympathies to the families and friends of the victims.

"These were the most heinous of offences and the grossest breach of the duty of trust he owed as a doctor to the victims, all of whom were trusting patients.

"Taking all the circumstances into account I have decided that nothing less than a whole life tariff should apply in this case."

James Purnell, the Labour MP for Stalybridge and Hyde, where Shipman committed many of his crimes, welcomed Mr Blunkett's announcement.

Kathleen Grundy: Her death started inquiry

Mr Purnell said: "I am reassured that David Blunkett has made clear today in answer to my Parliamentary question that Harold Shipman should never be released.

"This will be of some comfort to the families of those he murdered at this sensitive time when they await the findings of Dame Janet Smith next week."

The case of Kathleen Grundy first brought Shipman's activities to the attention of the police.

Shipman murdered Mrs Grundy, an 81-year-old former mayoress, at her home then forged her will to make himself the sole beneficiary of her estate.

Mrs Grundy's daughter Angela Woodruff raised the alarm and contacted police.