The government's plans to reform the benefits system are "on time and on budget", Work and Pensions Secretary Iain Duncan Smith has insisted, dismissing Labour claims that they are "a car crash in the making".
Mr Duncan Smith plans to introduce a universal credit to replace a string of income-related work-based benefits, aiming to ensure that people are always better off in work than they would be on benefits.
But 70 organisations involved in the benefits system said over the weekend they were worried about how the new system would work.
At question time in the Commons on 10 September 2012, Mr Duncan Smith dismissed suggestions from his opposition counterpart Liam Byrne that there was "chaos" within government over the reforms.
Mr Byrne sought to highlight a discrepancy in the estimate of the cost produced by the Office of Budget Responsibility (OBR), the UK's fiscal watchdog, and the Treasury.
"Now it's quite clear that the Treasury thinks there's a state of chaos around universal benefit, the Cabinet Office thinks there's chaos, Number 10 thinks there's chaos," he said.
The shadow work and pensions secretary called on Mr Duncan Smith to publish the business case for the plans.
"Is there something he's trying to hide?" he asked.
Mr Duncan Smith retorted: "There is absolutely nothing to hide here."
He invited Mr Byrne and his team to the department to "look through some of our business matters", adding: "I will show him how we are on time, on target and on budget."
Mr Duncan Smith concluded: "Over the weekend, he referred to universal credit as a 'car crash in the making'.
"I need no advice from the man who sat there and produced the biggest car crash in economic history in Britain."