You can tell ministers are in trouble when they start peddling distortions on the scale we've seen from Iain Duncan Smith this week. IDS is in trouble. And he knows it.

Next week, the beleaguered Work and Pensions Secretary comes to the Commons to defend the indefensible. The comprehensive failure of George Osborne's budgets has forced the independent Office for Budget Responsibility (OBR) to revise up its forecasts for the claimant count by a third of a million. That's pushed up welfare spending by an eye-watering £13bn. To pay that bill, IDS has been asked to push through a strivers' tax - more than 60 per cent of which will come from working families - on top of the £14bn already removed from tax credits, while Britain's richest citizens get a £3bn a year tax break.

It’s unjustifiable. And IDS knows it. So this week, we've had a very muddled attempt to make up some kind of case.

First, we had a made-up story that tax credit fraud had jumped by 58 per cent. This claim lasted about as long as it took Channel 4's FactCheck to gently point out, that IDS couldn't actually add up and the sums were wrong. Then we had a new line of attack. Benefits are rising faster than earnings. Except they're not. In the last ten years wages have risen faster than Jobseeker's Allowance, and the OBR tells us wages will power ahead of inflation in the next four years.

Then Nick Clegg tried to claim Labour was being inconsistent to low paid public service workers. We back a 1 per cent pay freeze, so why not a 1 per cent benefits cap? Because we've always said that 1 per cent should be an average with a tougher squeeze for the best paid public servants to fund higher pay rises for the lowest paid.

It's all fairly desperate stuff from a government that's trying at all costs to avoid admitting that the lion's share of the savings will come from working families' tax credits. So the real question in next week's debate is this: how can the government justify cutting working families' tax credits to pay for their failure to get Britain back to work - when millionaires are being given a tax cut? Right now working people are being hit with a double whammy. Wages are stagnant and tax credits are being slashed whilst at the same time the cost of living goes through the roof as anyone who boarded a train today will tell you.

The basic truth that IDS won't confront is simple. The best way to get welfare spending down is to get Britain back to work. But his much vaunted welfare revolution is in tatters. The Work Programme is literally worse than doing nothing. Universal Credit is beset with IT problems and has already been raided to pay for rising dole bills. Now the benefit cap is being pushed to the back end of the year because it’s a mess. Next week's Welfare Uprating Bill does nothing to address any of this. It does nothing to create a single new job.

More than half of the people currently out of work have been so for more than six months but the government isn’t lifting a finger to help. The Youth Contract is nowhere to be seen and the all too predictable result is youth unemployment still hovering around a million. That's why this government should be looking at far more concerted action to get Britain back to work with ideas like Labour's proposed tax on bankers' bonuses to create a fund big enough to get over 100,000 young people back into jobs.

There will plenty more smoke and mirrors from the government over the coming months but they can't disguise the reality of this Bill. It is a strivers’ tax which hammers hardworking families. The vast majority of the households hit are in work. Those are the people this government wants to cover the cost of their failure whilst 8,000 millionaires receive a tax cut worth an average of £107,500. If this government wants a battle over fairness whilst they are taking from hardworking families to fund a tax cut for the wealthiest, Labour is ready to take it on.