IDS says single mothers could keep fornightly benefit payments But we also recognise that, in the development of universal credit, there will always be some people who will need additional support. We are looking at and trialling that and making arrangements. There will be a range of budgeting support services available for those people to help them prepare. Jane Ellison, the Conservative MP for Battersea, south London, said single mothers in her constituency were worried that they would not be able to cope with monthly budgeting. Mr Duncan Smith said that for some claimants, "there may be interim two-weekly payments." "One of the great problems we have had is that, when people who have been unemployed go into work, they find it very difficult to cope with having to suddenly take on and manage their arrangements," he said. Mr Duncan Smith is widely believed to have refused to become Justice Secretary during David Cameron's Cabinet reshuffle last week, after reports that the Treasury wanted to axe the flagship welfare scheme amid fears the cost will rise. Labour's Shadow Work and Pensions Secretary, Liam Byrne, said that the Office of Budget Responsibility had forecast the extra cost of Universal Credit would be £3.1 billion in 2017. He demanded to know why the Treasury had said the cost must not rise more than £2.5 billion. Mr Duncan Smith said the OBR "agrees with me, which strangely enough agrees with the Treasury." Our view is that we will roll this out at £2.5bn a year as estimated.