People on fixed incomes face cuts in their living standards because 'astronomical'' household bill increases are not being matched by rises in benefits, the Tories said today.

Shadow work and pensions minister David Ruffley said changes to Government payments because of inflation were often not enough to make up for rises in gas and electricity bills or council tax rates.

He asked whether the methods used to calculate inflation could be adjusted so groups like pensioners were not left worse off.

He told the Commons, during a debate on adjustments to benefits that there were: 'Important questions about whether different groups in our society suffer from different inflationary pressures.''

Pensioners faced 'much higher'' utility bills and council tax levels than was reflected in the changes to their benefits, he said.

'The question we have to ask when looking at the merits of this order is will the uprating cover the increased cost of living that any particular group drawing that benefit is subject to.''

Work and Pensions Minister James Purnell questioned the practicality of any measure that proposed different inflation rates for different groups.

'Would they start to have different inflation rates for people in the north, people in the south?

'Would you start to have different inflation rates for people in their 20s or 40s?''

'Where are you going to stop?''

Mr Ruffley said many poor pensioners were not taking up benefits they were entitled too - such as council tax benefit.

Moving some pensioners from 'just below'' the poverty threshold to 'just above'' it was 'not really what it's about''.

He said there were many 'depressing statistics'' about fuel poverty among older people and said it had doubled since 2004.

'Tackling pensioner poverty must continue to be a top priority for any government.''

In 2004/05 there 1.8 million pensioners living in poverty but there were also 1.6 million pensioners who were not claiming pension credits, he claimed.

He added: 'One cannot have a sensible discussion about the uprating of these benefits...without also understanding the other part of the equation is the take-up of these benefits in the first place.''

He said many pensioners were not getting council tax benefit because they were not claiming it.

For the Liberal Democrats, David Laws said that the UK faced the 'bizarre situation'' of having one of the highest employment rates in Europe but also more children in homes with no adult working than any other country in the EU.

He said that of the 464 different benefits and allowances, 130 were not uprated at all. 'So in other words this is really an uprating and non-uprating statement,'' he said.

Mr Laws said the Winter Fuel Payment had not been uprated this year and there had not been an uprating since 2001.

'Perhaps that is why the DTI...indicated that it is expecting the number of people in fuel poverty not to disappear as is the Government's target, but to double from one million to two million between 2004 and 2006,'' he added.

Mr Laws branded the benefits system 'messy and complex''. He said it was full of 'historic anomalies'' and blamed ministers for an 'over reliance'' on means-testing.

Winding-up the debate, junior work and pensions minister James Plaskitt said the winter fuel allowance had risen from £20 to £200, with an additional £100 available to households with a pensioner over 80.

He hailed the uprating as 'another step away from the levels of pensioner poverty'' inherited by Labour in 1997.

The Order implementing the benefit increases was approved without a vote.