After eight years, the murder of James Bulger and the fate of his killers remains one of the most sensitive issues confronting a home secretary.

From Kenneth Clarke to David Blunkett, they have been acutely aware of the national wave of horror that greeted the story of Robert Thompson and Jon Venables abducting and battering the Liverpool toddler to death.

In the wake of the killing, Mr Clarke announced tougher penalties for joy-riders and "bail bandits", as well as a shake-up of the police. He coupled the moves with a plea for politicians to "spend more time condemning criminals and less producing mealy-mouthed excuses for them". His Labour shadow, Tony Blair, competed to sound tougher.

By the time Thompson and Venables were jailed for life, with a recommendation that they serve at least eight years, Michael Howard had taken over at the Home Office. Following a national outcry over the sentence, the minimum spell behind bars was raised to 10 years by the Lord Chief Justice, Lord Taylor and then to 15 years by Mr Howard.

He explained that the case called for a "higher tariff", also disclosing that he had taken into account one petition signed by almost 300,000 people, as well as 20,000 coupons sent in by readers of The Sun.

Humiliatingly for him, that ruling was overturned two years later by the Law Lords. The European Court of Human Rights also criticised Mr Howard for intervening over the boys' sentence, ruling that it was a breach of human rights for a politician, rather than an independent judicial tribunal such as the court, to set an offender's tariff.

His successor as home secretary, Jack Straw, knew he was powerless to prevent the freeing of Venables and Thompson – and the inevitable public outcry that would follow.

Early last year he referred the case to the Lord Chief Justice, Lord Justice Woolf, the most senior judge in England and Wales, who ruled that they were eligible for release and should not go into the adult jail system.

Mr Howard, free of the quasi-judicial constraints of office, said he "very much regretted" the decision. He said: "I do not believe that it reflects what the trial judge had described as the unparalleled evil nature of the offence."

Announcing yesterday's decision, David Blunkett, promoted to Home Secretary in this month's cabinet reshuffle, stretched the conventional language of parliamentary written answers to the limit in his condemnation of the crime.

Mr Blunkett said: "The circumstances of the killing were horrific and had a profound impact throughout the UK and beyond. We will never forget it and I can well understand how distressing it is for James' family now to hear this news."

The shadow Home Secretary, Ann Widdecombe, said: "The tarrifs imposed by Michael Howard of 15 years were more appropriate, given the gravity of this offence.

"If there was such objection to sending them to adult prison, then other arrangements could, and should, have been made for their secure detention."