No 10: We have signed away asylum rights

Downing Street admitted today that the Government has signed away its right to cut the number of asylum seekers in Britain.

The Government confirmed that Michael Howard's plans to put a cap on numbers would be unlawful because of European directives agreed last year.

The extraordinary twist to the immigration furore was revealed by Brussels officials who pointed out that the Government gave up any power to cut numbers when it agreed a directive last March making asylum an a matter for EU law.

The claim provoked surprise, coming hours after the Tory leader put tough immigration controls at the heart of his election campaign.

Under Conservative plans, Britain would withdraw from the 1951 UN convention on refugees and impose a 10,000-20,000 a year ceiling on asylum claims.

But No 10 said the convention had become enshrined in EU law by a directive agreed last March, so Mr Howard could not carry out his policy without EU permission.

This is embarrassing for both party leaders, because neither highlighted the loss of power until the EU itself pointed it out. The Tories insisted they could renegotiate the EU law - but No 10 said that was virtually impossible.

The qualifications directive signed in 2004 duplicates part of the 1951 convention and makes it binding EU-wide. It obliges all member states to accept asylum claims from anyone fitting the criteria.

Downing Street said it would be

impossible for Britain to opt out without unpicking a series of linked agreements on asylum which were helpful to Britain.

The UN convention is also linked to the European Convention on Human Rights - also now enshrined in UK law.

The Prime Minister ' s spokesman said Britain had benefited from European asylum laws which, for example, allow us to deport claimants who arrived here via other member states.

He said: "The important thing for this country was to stop the process of asylum 'shopping'. If Britain were to opt out of one directive, the whole process would stop."

Frisco Roscam Abbing, spokesman for EU Justice Commissioner Franco Frattini said Britain had given up previous opt-outs from EU law covering migration since 1997.

He insisted the rules could not be changed even if Mr Howard becomes Prime Minister. "There is nothing in these protocols that allows a British government to opt back out again," he said.

Mr Howard could expect legal action from Brussels if he attempted to curb asylum numbers, Mr Roscam Abbing added. "Say they set a quota of 10,000 a year. Well, the 10,001st case could say to a British judge, 'Your government is bound by EU rules and is not at liberty not to consider my claim."

David Davis, the shadow home secretary, said a Tory government would seek to overturn the EU agreements. "We had a pretty good idea we would have to renegotiate," he said.

Labour was on the back foot over Mr Howard's immigration proposals yesterday, though Tony Blair branded them " unworkable". A five-year plan for immigration is to be announced shortly by Home Secretary Charles Clarke.