By Nick Assinder
Political correspondent, BBC News website
Renaming incapacity benefit "employment and support allowance" is going to be the easy bit for Tony Blair.
Labour MPs may rebel over benefits changes
Why such a re-branding is necessary remains a bit of a mystery, although it is claimed the aim is to end any suggestion the benefit is long term or for life.
It is all part of the carrot and stick approach which is supposed to ensure those who really cannot work receive extra cash and those who could take jobs are "encouraged" to do so.
And it is the element of encouragement, or "incentivisation", that will cause the greatest controversy.
Despite the reassurances made by Work and Pensions Secretary John Hutton in the Commons, opponents fear it is code for compulsion. The fact that the Tories support it will only add to some Labour backbenchers' fears.
As widely predicted, the welfare proposals will aim to remove one million of the 2.7 million claimants off the benefit over a decade, with a substantial reduction in the annual £12.5bn cost of the scheme.
But opponents remain deeply concerned that some of the most vulnerable in society are being targeted to save the government money, and that there will be undue pressure placed on them to come off benefits.
The prime minister insists the only aim of the proposals is to help the 90% of IB claimants who want to get back into work.
It is not, he reassures his rebels, about targeting the weak or forcing them off benefit.
Mr Blair has faced previous opposition to welfare reform
Yet the element of compulsion, through benefits cuts for those refusing to take part in the new job finding initiatives, will prove hugely controversial.
There will also be opposition to plans to offer GPs "incentives" for cutting the number of sick notes they hand out and the placing of "employment advisers" in surgeries.
However, other measures like means testing the benefit and capping the time individuals are allowed to claim it appear to have been abandoned in the face of opposition.
The last time Mr Blair tried to reform it, in 1999, he suffered a rebellion by 67 of his own MPs - just about the size of his current majority.
There is still significant opposition on his back benches and rebels are bound to launch a high-level campaign against any moves they feel are too draconian.
Mr Hutton did his best to persuade his MPs that his detailed package of measures were all about increasing people's opportunities and sparing them from years of unnecessary joblessness and moving towards a society where 80% are in work.
He even went so far as to appeal to old emotions by declaring he was out to "bring this shameful legacy of Thatcherism to an end".
That aimed straight at the hearts of Old Labour MPs, many of whom are deeply worried about the proposals. But elsewhere their concerns were probably only heightened.
It is still difficult to predict the level of any backbench rebellion and there is now to be a three-month consultation period before any White Paper, let alone legislation, is produced.
It is during this period that the full extent of the expected revolt will be gauged.