The leader of the campaign to abolish the council tax, which has resulted in two elderly members being jailed for non-payment, said that "dozens" more pensioners were willing to go to prison for the cause.
In a warning to Tony Blair, Christine Melsom, 64, said the IsItFair? campaign was attracting new members by the hour and would continue to fight until the tax was replaced with a fairer system linked to ability to pay.
Christine Melsom: 'There is a lot of anger out there' She said that Alfred Ridley, a 71-year-old retired vicar, and Sylvia Hardy, 73, a former social worker, would not be the last to be jailed and issued a warning that the grey vote revolt could cost Labour dear.
"In the end something will have to give," she said. "We cannot have jails full of elderly people. But we will fight until this tax is scrapped. We could have another poll tax situation on our hands.
"This is not just a pensioner issue; it affects everyone and anyone who thinks we are just a load of placard-waving pensioners should bear in mind that they may suffer next."
Miss Hardy, who was released on Tuesday, 24 hours into a seven-day sentence after a mystery backer paid her Ј53 arrears, has already received another summons and says she is willing to go back to jail.
Mrs Melsom started the campaign in September 2002 when she and her husband John, 80, received a council tax increase of 15.5 per cent from Hampshire county council.
Mrs Melsom estimates that the campaign has more than 30,000 members and says it has grown rapidly since the prison sentences were imposed. It suggests replacing the tax by slightly increasing VAT and income tax.
Senior members have been in great demand to speak at meetings all over the country.
She said: "It has become really huge. People don't appreciate that we have been going for a couple of years, held protest marches, had discussions with the Conservative and Liberal Democrats - Labour has refused point blank to see us - and sat on parliamentary committees.
"Recently we have done meetings in Selby, Finchley and Southampton and have others coming up in Taunton and London."
The group relies on donations of stamps, envelopes and ink cartridges for printers as it has no funding, Daily Telegraph reports.