By Nick Assinder BBC News Online political correspondent

Seldom has Home Secretary David Blunkett appeared more ill an ease, almost apologetic, than over his policy on cannabis.

Blunkett prefers to be seen as hard line

The minister, who usually revels in his hard man image, is having to justify his decision to downgrade dope to a class C drug. And he patently does not enjoy it.

He has confessed that, unlike some of his tougher policies, he "agonised" over this one.

He has even had to launch an expensive advertising campaign to warn people that, despite the re-classification, cannabis is still illegal and potentially dangerous.

And, speaking on the Today programme, he insisted that if he smelled youngsters smoking cannabis in public he would turn them in to the police.

Leapt in

None the less, the whole world has viewed his new policy as a liberalisation of the law - not the sort of headlines Mr Blunkett usually attracts, or enjoys.

He prefers, it seems, to be seen as the toughest Home Secretary since, well, Michael Howard.

Cannabis is still illegal

And now he has abandoned that territory on this particular policy, the Tory leader has leapt in.

Mr Howard, who more usually finds himself attacked for refusing to announce policies, has lost no time in declaring he would reverse this particular one.

And suddenly Mr Blunkett finds himself in what was once traditional Labour territory - being portrayed as soft on crime compared to the Tories' toughness.

The opposition to the Home Secretary's policy does not stop with the Tories, however.

Liberal agenda

There are plenty on his own backbenches who believe the new policy is dangerous because it may confuse youngsters by suggesting smoking cannabis is acceptable and safe, even legal.

If opponents' fears that this could signal the start of an upsurge in drug taking prove accurate, it could yet come back to haunt Mr Blunkett.

And they are asking why the government got itself into this position when there was no political imperative to change the law.

In fact, the policy was driven more by policing practicalities than any liberal agenda.

Mr Blunkett had been urged to make the change so Britain's police forces, particularly in some inner city areas, could concentrate more effort on tackling the real killer drugs like crack and heroin.

Concerns about the message being sent to youngsters by the existing policy, which put cannabis in the same category as harder drugs, was also a consideration.

Ministers must be hoping that there will not be any significant fall-out from the re-classification.

But, if opponents' fears that this could signal the start of an upsurge in drug-taking prove accurate, it could yet come back to haunt Mr Blunkett.