By Nick Assinder BBC News Online political correspondent

Three months ago the NHS was top of Tony Blair's agenda, then the focus shifted to crime - now, without any doubt, it is asylum and immigration.

And whenever we hear that Tony Blair has taken personal charge of an issue, it is a sure-fire sign that there is a bit of a panic gripping the government.

It is certainly true that, over the past couple of years, the asylum issue has escalated from an irritation to a major challenge to the government.

Issue can spark anger

It is a problem that affects the whole of Europe but there is the persistent suspicion, based on some evidence, that Britain is suffering the brunt.

It is an issue that can rapidly fan flames of resentment and anger in the areas most affected and it was clearly responsible for the recent rise in extreme rightwing parties across Europe.

It is also an issue that can pile huge strains on the relationship between the government and other EU states.

And many Labour MPs are concerned that the government does not take measures that infringe human rights.

Do something

The row over the Sangatte camp in France and the allegations about the allegedly half-hearted security around the camp is a prime example.

It has whipped up widespread resentment in Britain and has real potential to cause serious divisions between London and Paris.

Blair wants EU help

The result of all this is that Tony Blair is desperate to be seen to be doing something.

Just as there has been a flood of initiatives of the health service and then crime, we are now starting to see a series of new suggestions about how the government may tackle asylum.

There is clearly something in the air over Sangatte, Mr Blair has attempted to drive the issue to the top of the looming EU summit in Seville and there are now claims he wants to use the navy to tackle people traffickers in the Mediterranean.

Mass deportations

And hardly a day now goes by without one minister or another addressing the issue.

There is talk, some of it probably overheated, about imposing sanctions on other EU states who refuse to take back bogus asylum seekers and of mass deportations.

Despite all this, however, it is still far from clear exactly where the government is going over this hugely sensitive issue.

The prime minister is fully aware of the sensitivities of tackling the issue, but he also knows that the time has come for concrete policies.

This, however, is not something he can do alone.

He has to have the support of his EU partners, and Seville will offer him that opportunity.

This could be a perfect opportunity for Mr Blair to use that newfound influence he likes to claim his government now has in the EU.