Welfare reforms are about fairness, says IDS The Work and Pensions Secretary admitted that peers may want to "vent" their feelings over a planned £26,000-a-year benefit cap, the equivalent of £35,000 before tax. "I simply make the point to them that the purpose of this is not to punish people but it is to give fairness to people who are paying tax, who are commuting large distances because they can only afford to live in the houses that they have chosen," he told Sky News. It is also about fairness to those who are on these benefits; it is not fair to trap somebody in an expensive house which they cannot afford then to go to work on the back of, because they would lose their housing benefit if they went to work - so they are disincentivised from going to work. This is a ridiculous system that we have inherited. Mr Duncan Smith's remarks came as ministers braced themselves for a bruising clash with the House of Lords over the planned reforms. A combination of Church of England bishops and rebel Liberal Democrats are threatening to derail the planned £500-a-week cap when peers vote on the measure today. Former Lib Dem leader Lord Ashdown became the most high-profile figure so far to speak out against the plans, denouncing them as "completely unacceptable" in their current form. Mr Duncan Smith said the proposal would save "something in the order" of £600 million towards deficit reduction. He added that no-one would be homeless as a result of the changes. The Work and Pension Secretary's defence of the proposals come as Lord Ashdown said that as president of the United Nations' children's agency, Unicef, he was not prepared to support them in the vote on amendments to the Welfare Reform Bill. Despite the divisions in his own ranks, however, Deputy Prime Minister Nick Clegg has said he is fully signed up to the changes. Mr Clegg suggested there was some scope for softening the impact of the changes through "transitional arrangements" around the introduction of the cap. However, he flatly rejected an amendment tabled by the Bishop of Ripon and Leeds, the Rt Rev John Packer, which would exclude child benefit payments from the £500-a-week limit. Ministers appear determined to ride out the opposition, believing there is strong public support for their plans to curb the benefits dependency culture and "make work pay." Employment Minister Chris Grayling last night acknowledged some families would be forced to find new accommodation as a result of the changes, but strongly defended the measure. "There certainly will be people who have to move house as a result of this, who have to move to a part of town they can afford to live in, but surely that is right," he told BBC Radio 5 Live's Pienaar's Politics. However, the vote poses a dilemma for Labour who have to decide whether they want to try to inflict a damaging defeat on the Government, even if it means taking the blame for blocking a measure popular with much of the public. Party officials were staying tight-lipped last night on whether they would back the bishop's amendment, saying they would be concentrating on their own compromise amendment designed to protect families facing losing their homes. "Labour won't be voting against the benefits cap because we support the principles and the responsibility to take a job if you can work," a spokesman said. But we will be seeking to amend the Bill, to bring a compromise between the bishops and the Government because we don't think council taxpayers should be hit with a massive bill for homelessness. However, Mr Grayling said Labour now needed to decide where it stood on the issue. "Does it want to deliver the kind of change to the welfare state that all the evidence says the public overwhelmingly want or is it going to line up on the other side and try and chip away at reforms that are essential?" he said. Mr Duncan Smith told the BBC Radio 4 Today programme that impact assessments for the cap would be published later. "We do not believe there will be an increase in child poverty," he said. Our department does not believe that you can directly apportion poverty to this particular measure. He insisted the Government was going help families "find a way out," by getting them into work. "The reality is that (at) £26,000, it is very difficult to believe that families will be plunged into poverty," Mr Duncan Smith said. The numbers of families involved in this in relation to the whole number of families who are on benefits is relatively very small. Mr Duncan Smith criticised the definition of homelessness used by critics, saying it was based on children sharing rooms rather than whether people had somewhere to live. No-one would be made homeless in the general public's understanding of the term, he said. The Cabinet minister said bishops were quite entitled to express their views on the policy. "I just wish that occasionally they would call us to get their figures right," he added.