In an email to Conservative supporters Iain Duncan Smith has accused Labour of having no plan to reduce the deficit:
Today, Labour will vote against capping benefits at 1% for the next 3 years - a double blow to the taxpayer who has to foot the bill.
Under Labour, our welfare system spiralled out of control with the welfare bill rising by 60%, costing every household in Britain an extra £3000 a year.
In the last 5 years, those on out of work benefits have seen their incomes rise almost twice as fast as people in work - at a rate of 20% compared to an increase in average earnings of only 12%. For Conservatives, this vote is about fairness. Why should the taxpayer pay more to sustain welfare payments while at the same time earning less?
Labour vote time and again against everything this government is doing to get welfare spending under control. But they don't say how they would pay for all this. By voting against our measures, Labour's Ed Balls would clearly be happy with more borrowing to pay the welfare bill - this would saddle every working household in the UK with almost £5,000 of extra national debt.
It's clear Labour has learnt nothing. Labour's plan is to spend more, borrow more and tax more. Where's the fairness in that?
Our plan is clear - to deliver stability to the public finances and return fairness to welfare.
MPs have voted in favour of a Government measure to cap benefits rises. The Work Secretary says it will save £5bn from the welfare bill.
The Department for Work and Pensions has calculated the savings that the exchequer could expect if the benefit cap passes this evening.