The No2 ID campaign is on course to hit the £100,000 target it set for a legal fund to defend anyone prosecuted for refusing to register with the identity cards scheme.
The campaign's national co-ordinator, Phil Booth, promised last month on website Pledgebank.com to refuse to register for an ID card and to donate £10 to a legal defence fund - but only if 10,000 others made the same pledge by 9 October.
By Monday, 9,525 people had already signed the pledge, and Booth is confident the campaign will have raised £100,000 by the end of this week, given the speed at which people are signing up online.
He added: "We shall shortly be launching a pledge we hope will raise £1m - this time from those people who can't refuse to register, for whatever reason, but who will support those who do."
Many who signed the pledge last week feared the Government would use the London bombings to speed the passage of the ID Cards Bill through Parliament. One said: "We can expect the Government to claim that ID cards are an essential weapon in the fight against terrorism. Those who remain opposed to the scheme on the grounds of cost and civil liberties will be smeared as supporters of terrorism and, by implication, enemies of the state."