A row has broken out over the status of Tony Blair's pledge to slash the number of asylum seekers coming to Britain "by 30 or 40 per cent in the next few months".

It has been reported that David Blunkett, the home secretary, does not believe the prime minister's aim is achievable.

A government spokesman said Tony Blair was not setting a target but giving "an indicator of progress".

"The prime minister said the halving of the applications was a longer term objective," he added.

The Conservatives attacked government "confusion" on the issue.

"There is now a state of complete confusion. Does the government have a target or a commitment to reduce asylum applications by half by September or not? If so, how does it intend to achieve this result?" asked Oliver Letwin, the shadow home secretary.

Human rights and refugee campaign groups are also to ask the High Court to rule on new legislation that stop asylum seekers who do not lodge a claim as soon as they arrive in the country from obtaining benefits.