Campaigners say that a network of anti-ID card groups, ranging from hackers to anarchists, plans a series of assaults in the coming months to try to block the scheme. A £1 million fund is being raised to help pay legal fees if, as expected, prosecutions are brought once the cards become compulsory, probably in 2010.

'We have to show these [people] that we did not vote for them and that we will bring them down. This is the poll tax all over again. I am prepared to do time for this,' runs one entry on the No2ID campaign website. Another says: 'I'm not an anarchist, but we're getting to the stage now where I think peaceful protest isn't going to work.'

The Home Office estimates that around 17 per cent of adults - up to four million people - oppose the cards. A recent ICM poll, commissioned by No2ID, found that 43 per cent believe they are a 'bad' or 'very bad' idea.

'Whichever poll you believe,' says Phil Booth, head of No2ID, 'there are millions who just won't do it.'

Many of the tactics to be used by the campaigners have been borrowed from Australia, where in 1987 the government scrapped plans for ID cards after a network of 'refusenik' organisations obstructed the scheme.

Booth was at the Glastonbury festival last weekend drumming up support. So far 7,000 people have pledged to resist the scheme.

He says they could be followed by hundreds of thousands of others willing to obstruct the whole scheme. 'Our next pledge will be to raise £1 million for a fighting fund from people who feel they cannot actively reject the scheme, but are sympathetic to those who will.'

The phased nature of the scheme's launch - with ID cards initially distributed on a voluntary basis to Britons and compulsorily to foreign workers from 2008 - has been seized on by campaigners as proof that the government knows the strength of the opposition. Ministers have yet to commit themselves to a date when the cards will become compulsory for all.

'The government appears to have learnt from the poll tax, in that it's not going to introduce it in one go,' said a man called Nathan who helps to co-ordinate the Defy ID network, a loose, pan-national organisation that advocates direct action.

'In the same way people broke the law by refusing to pay their poll tax, we may see similar acts of disobedience. There's a diversity of tactics people are going to use, from targeting the companies involved to buying shares in them so you can attend and disrupt their annual meetings,' Nathan added.

The Passport Office, which in the autumn will roll out new biometric passports with scans of applicants' faces, fingerprints and irises, will be a key target. Initially only those who need to renew their passports will be required to have the scans.

Opponents are preparing to launch a co-ordinated mass application to the Passport Office over the summer. The applicants would be issued with the current non-biometric passports that would, theoretically, be valid for 10 years. The surge in applications would cause a major headache for the office, which has suffered backlogs due to IT failures.

'Given the Passport Office's past form, being required to process a big increase in applications is something that could cause significant problems,' Booth said. A second front will be the launch of a legal test case challenging enforced fingerprinting on passports which the shadow Attorney General, Dominic Grieve, said last week may be illegal.

Individuals are being encouraged to launch their own forms of resistance. One idea is for people to refuse to touch their fingers on the scanners, causing backlogs at the 70 ID card centres.

Campaigners are also being instructed to cross their eyes when in front of the iris scanners. Another suggestion is for people to say they have undergone a religious conversion, and insist on wearing burqas - which cover the face - in front of the scanners.

Booth said: 'There will very definitely be resistance. As with the poll tax, mass refusal to comply occurs when people feel something is deeply unfair.'