· 25% now strongly against their use, says ICM survey · Majority concerned about sharing of personal details

The number of people strongly opposed to the introduction of a national identity card scheme has risen sharply, according to the results of an ICM poll to be published today.

Those campaigning against ID cards said last night that the poll, with results showing that 25% of the public are deeply opposed to the idea, raises the prospect that the potential number of those likely to refuse to register for the card has risen. If the poll's findings were reflected in the wider population, as many as 10 million people may be expected to refuse to comply.

The ICM survey also shows that a majority of the British people say they are "uncomfortable" with the idea that personal data provided to the government for one purpose should be shared between all Whitehall-run public services.

The poll, commissioned by the Joseph Rowntree Reform Trust, shows that British public opinion is deeply split over the introduction of identity cards, with 50% against the idea and 47% in favour.

Recent disputes over the further delays to have hit the project have strengthened opposition to the scheme, with those who think it is "a very bad" idea rising from 17% last September to 25% now. This compares with only 12% who think that pressing ahead with ID cards, which will cost around £93 per person when combined with a passport, is a "very good idea".

In the aftermath of the government's recent embarrassing losses of confidential personal data, public opinion appears to have turned sharply against the idea of sharing information within Whitehall and the creeping introduction of the "Big Brother" state.

A majority - 52% - say they feel uncomfortable with allowing "personal information that is provided to one government department to be shared between all government departments that provide public services".

However, the poll does show that clear support exists among the public for setting up a central identity register and collecting personal travel details on everyone coming in and out of Britain. It also reveals some support for the creation of a separate database about every child, including details about their parents and carers.

Phil Booth, of the No2id campaign, said: "With a quarter of the country deeply opposed to ID cards, and a clear majority reluctant to have their personal information shared even for public services, the government needs to fundamentally rethink its database state.

"These figures suggest that millions will simply refuse to comply."

He said the results showed that between 10 million and 15 million could refuse to register for the card.

The Liberal Democrats' home affairs spokesman, Chris Huhne, said that public opinion was moving sharply away from the government's ID card scheme as more people understood how intrusive it was going to be, and the more they saw that officials were unable to keep confidential and personal data secure.

Huhne said: "These polling figures are a body-blow to the government's hopes of introducing ID cards and the associated personal database, as they suggest a large pool of people who may refuse to cooperate."

Leaked Home Office documents suggested last month that the planned large-scale voluntary rollout of national identity cards for British nationals had been delayed by two years until beyond the next general election.

The first ID cards will be introduced in December this year for foreign nationals resident in the country. It will follow a pilot scheme to be run in London from April to test the technology. The prime minister, Gordon Brown, has confirmed that legislation will have to be introduced before it becomes compulsory for British nationals to register for the ID cards scheme.

· The ICM poll interviewed a represent-ative sample of 1,008 people between February 1 and 3, 2008