By Nick Assinder BBC News Online political correspondent

It is a scene from scores of old black and white films.

The train clatters across the sullen, usually rain sodden, European countryside.

The travellers sit anxiously in the austere, wood panelled carriage as a nervous looking guard and two Gestapo or KGB thugs (take your pick) fill the doorway and bark: "papers".

There's a pause of almost unbearable tension as our heroes hand over their documents and wait as their would-be tormentors scrutinise every mole, wrinkle and water mark.

Papers please

Their futures, indeed their very lives, depend on the outcome of this encounter.

It is a powerful image born out of wartime fears and post-war paranoia.

And, unfortunately for the government, it is one that will forever be attached to identity cards.

Poll tax

Calling them entitlement cards appears unlikely to help. For many, that simply smacks of New Labour doublespeak, or spin.

If you choose not to have one does that mean you are somehow unentiled? Obviously not, but it undermines the positive spin being put on things.

Cards will help immigration

And it didn't help Margaret Thatcher when she insisted on calling the poll tax the community charge - not even her own ministers always got that one right.

It is also pretty unconvincing when ministers insist the government is totally neutral on the issue.

If that was really the case then it begs the question of why they raised the issue at all.

By doing so, and then pointing out the advantages cards would apparently offer in the battle against fraud, terrorism and illegal immigration the government is signalling its tacit support for a scheme.

No offence

Probably the most powerful argument against ID cards as currently envisaged is the fact that carrying one would be purely voluntary.

That raises the next question for ministers of how on earth an entitlement card scheme can work against benefit fraudsters, terrorists or illegal immigrants if they are voluntary and not carrying one is not an offence.

The answer many fear is that those who choose not to carry the card will immediately be labelled as suspicious if stopped by the police.

Then there is the straightforward civil liberties argument and opposition to yet more state interference in citizens' daily lives.

Blunkett backed down on email

The arguments for some sort of card may outweigh all these disadvantages, however.

After all only a tiny proportion of people do not daily carry some sort of ID with them, be it a driving licence, bank card, work-related ID or even bus pass.

Email snooping

Having a new card that could replace some of these and make some transactions simpler and faster might be a huge convenience.

That is probably why 90% of the French carry them even though it is purely voluntary.

Politically, however, this looks like another row the government could probably do without.

The prime minister is desperate not to be seen expressing a view and ministers do not want to be forced into yet another embarrassing climbdown similar to the one Home Secretary David Blunkett was forced to execute over email snooping.

As with that proposed legislation, powerful lobby groups are lining up against the plans, invoking the image of Big Brother.

They have already proved they can sway events and they now have ID cards in their sights.

That has led many to believe this will be defeated before the consultation process even gets properly off the ground.