THE country's biggest trade union has launched the most comprehensive attack to date on the Scottish Government's long-running council tax freeze, claiming the policy has been unfair on poorer households.

Public sector union Unison said wealthy households – those in Band H homes – were saving £441 per year as a result of the freeze, compared with £147 for those in the cheapest Band A homes.

In a report, the union flatly rejected Scottish Government claims that the policy was a "lifeline" for hard-up Scots and called for a debate on its future. Council tax bills have been frozen each year since 2007 when the SNP first took power at Holyrood.

The freeze was originally intended as an interim measure until the Nationalists promised local income tax could be delivered, but the proposal enountered fierce opposition and has remained on hold.

Councils have been threatened with mutlimillion-pound penalties if they refuse to keep freezing bills. Alex Salmond has claimed it is part of a "social contract" with the public to keep bills down in tough economic times.

However, Unison's report, based on information received under Freedom of Information laws, said council tax savings for those on modest incomes had been "far outweighed" by big increases in rent and charges for a range of services. The study cited rent rises in Edinburgh, for a three-bedroom council home from £61.57 per week to £85.55, equivalent to £1237 a year.

It also gave the example of school meals rising from £1.60 to £2.10 in Argyll & Bute, an increase of £200 per year for a family with two children, and the introduction of £10 weekly charges for day centres for elderly and disabled people in some council areas.

Dave Watson, Unison Scotland's head of campaigns, said: "People on modest incomes are having to pay far more for costs like their rent, school meals for their kids, and charges for care in day centres for their vulnerable relatives and still services are being cut back.

"Meanwhile those in the leafier suburbs benefit most from the unfair council tax freeze. It is not socially just or fair."

He added: "The freeze disproportionately benefits the wealthy, while charges are being increased and services cut. It's much fairer for everyone to pay a small amount extra in tax than have big increases in charges that bear no relation to ability to pay for services."

Unison's report said: "The Scottish Government claims the council tax freeze is a 'vital lifeline to hard-pressed Scots'. This is not the case."

The Unison report comes as Scottish Labour are conducting a controversial review of all Scottish Government spending to assess its affordability and fairness.

A Scottish Government spokeswoman said: "The council tax freeze, which has been fully funded by the Scottish Government, has helped ease financial pressure on all council tax-paying families in Scotland. Lower income households, who are liable for council tax, are estimated to see the greatest benefit as a proportion of their household income, with the average household set to benefit by around £1200 by the end of this parliament."