By Nick Assinder BBC News Online political correspondent

Tony Blair has recently been locked in a bare knuckle fight with the Tories over asylum - and he's just lost it.

If Iain Duncan Smith's proposals are ever put into practice, Britain will have by far its most draconian peacetime asylum laws and some of the toughest in Europe.

Duncan Smith: appealing to voters

The Tory leader has seized on rising public concern over this issue to come up with drastic remedies.

The prime minister attempted to get his retaliation in first at the weekend by suggesting he was contemplating "radical" new moves to deal with the problem.

But Mr Duncan Smith has now delivered the knockout blow. It is hard to think of anything the government can now come up with to out-bid the Tories on this one.

Too illiberal

Plans to lock up all asylum seekers, opt out of international conventions and even set quotas on refugees will cause a storm of protests from civil liberties groups.

The prime minister stirred up enough of a hornets' nest with his threat to pull Britain out of the European convention on human rights if his existing crackdown on asylum fails.

The Tory proposals go much further and will produce a stronger reaction.

Blair got in first

A similar proposal was floated by former shadow minister Ann Widdecombe before the last General Election.

Mr Duncan Smith is now likely to face precisely the same sort of reaction given to his predecessor William Hague when he raised the immigration issue and famously talked about Britain becoming a foreign land.

But, in the wake of 11 September and the growing terrorist threat, both the Tories and Labour have become increasingly hard-line on this issue.

Both leaders have clearly calculated that this is an issue that is whipping up real public anger.

Soft touch

Stories of former Taleban fighters being given safe haven and, presumably state support, in Britain, have sharpened people's fears over both imported terrorism and the scale of the asylum problem.

It is an issue that has been growing for years, sparked by the collapse of the old world order and the rising number of people fleeing repressive regimes.

It is no surprise the majority of asylum seekers to Britain come from Afghanistan, Iraq and Zimbabwe.

It is also the case that the numbers of refugees of all sorts has risen over the years amid allegations that Britain has become the "soft touch" of Europe.

The success of far right groups such as the British National Party in some local elections is put down to exploitation of people's fears over immigration and, now, terrorism.

But the main political parties have always been careful not to move onto their agenda.

Real threat

Many now fear that the desire to win public support is seeing some politicians more prepared to contemplate hard line measures than engaging in the difficult public argument about immigration.

In particular, the direct linking of terrorism and asylum seekers, will be seen as highly dangerous, provocative and out of proportion to the real threat.

It is claimed that, rather than improving things, the "crackdown" approach will only serve to confirm people's worst fears and whip up anti-immigration sentiments.

Supporters of such an approach insist, however, that it is no longer acceptable for politicians to bury their heads in the sand over the issue.

Leaving it to fester will, they claim, only inflame the situation further.

The only point of agreement is that this issue is highly dangerous.