In an effort to shore up support among Labour MPs, Mr Blunkett held a series of backbench briefings yesterday and enlisted the influential support of John Denham, home affairs select committee chairman.
David Davis, the shadow home affairs spokesman, was sceptical on a mixture of practical, libertarian and cost grounds. But he faced difficulties when Mr Blunkett unearthed a statement from Michael Howard in 2001 asserting identity cards were vital to the fight against crime and terrorism.
The Liberal Democrat home affairs spokesman, Mark Oaten, said he fundamentally opposed the idea and argued the money would be better spent on putting more police on the streets.