David Blunkett has conceded the government's crackdown on asylum seekers could lead to a £1 billion budget overspend.

Conservatives have described reports of a £1.47 billion cost for policing asylum applicants - only £434 million was budgeted for - as "terrifying".

Oliver Letwin accused the home secretary of presiding over a system which has "spiralled completely out of control".

Figures showing last year's cost of supporting those seeking refugee status was £1.05 billion, more than double the £403 million predicted by the Home Office, have been confirmed by Blunkett.