Millions of England's poorest households face huge council tax rises as local authorities are forced to cut benefits.
Centre-left Resolution Foundation warned today of a council tax crisis, with England's poorest households facing increases of up to £577.
The coalition will cut funding for council tax support by 10 per cent from April even as its two-year freeze on council tax increases comes to an end next year.
Devolved governments in Scotland and Wales have already pledged to cover the local shortfall, but in England the decision is down to each local authority - cut council tax benefits or cut spending somewhere else.
Well over two million unemployed people and nearly 700,000 already in work depend on the benefit, with the average council tax in England set at around £1,201 a year.
But the Resolution Foundation's researchers said today three out of four councils had decided to force their poorest constituents to cough up the cash.
Those unable to find more than 16 hours' work will have to stump up between £96 and £255 a year - as much as 8 per cent of jobseeker's allowance.
Tory Local Government Minister Brandon Lewis insisted the reforms were "ending the 'something for nothing' culture and making work pay."
But the councils will hit working households just as hard. A parent who works for the minimum wage stands to lose between £96 and £577 more to council tax.
The average worker on universal credit and council tax benefit will will lose around 81p to taxes and benefit cuts out of every pound earned: effectively paid for just 12 minutes of every extra hour they work.
War On Want campaigns officer Murray Worthy told the Morning Star the cuts revealed the government's "perverse logic."
He said: "In order to make the poor work, you need to make them poorer - but to make the rich work, you need to make them richer."
Thousands already could not afford basic groceries or fuel, but could try food banks or going without heating, he said.
But unpaid council tax was a criminal offence.
"It's almost beyond belief that a government could do this," he said.