20/03/2016 05:23 GMT | Updated 21/03/2017 05:12 GMT

This Budget Is Osborne's Nadir - How Long Before His Tory Colleagues Boot the Chancellor Out of Office?

Sometimes it's the people with whom we work most closely that end up knowing us the best. So it has proved with George Osborne and Iain Duncan Smith. IDS said this morning the Chancellor's policies are "damaging for the Government, damaging for the party and damaging for the public". He said David Cameron's administration is: "In danger of drifting in a direction that divides society rather than unites it". And he made the damning observation that the Government, and the country is: "Hamstrung by short-term savings", an acknowledgement that Labour was right to point out Tory spending cuts were simply too fast and too deep. The former Work and Pensions Secretary now opposes the welfare cap, one of the Government's flagship policies. It is a stunning development.

Duncan Smith's observation in his resignation letter to the Prime Minister was revealing. In it, he said: "I am unable to watch passively whilst certain policies are enacted in order to meet the fiscal self-imposed restraints that I believe are more and more perceived as distinctly political rather than in the national economic interest".

For once IDS has hit the nail on the head. George Osborne is a man who always puts his career before his country. The nation's economic interest is not his primary concern. If it was, he would not have claimed that a booming economy meant he had £27billion to fund pre-election giveaways in his Autumn statement last year, only to blame a faltering economy six months later for a financial black hole that will leave the country £56billion worse off over the next five years. His desire to succeed David Cameron as Prime Minister prompted him to cut taxes for the wealthiest, despite warnings from experts that he couldn't afford to do so, and plug the financial shortfall by taking money from the disabled. That decision, in the words of one of Iain Duncan Smith's closest allies, was 'morally indefensible'. A good number of backbench Tory MPs share the former welfare secretary's disgust over Osborne's £1billion raid on Personal Independence Payments, and it is now likely to be reversed.

Yet again, one of Osborne's budgets is unraveling before his eyes. Osborne is remarkably error-prone for a man who has only ever been focused on his own political advancement. He has now delivered eight budgets in his six years as Chancellor. Virtually every one one of them has been a disaster. His March 2012 budget was famously labeled an 'omnishambles' after taxes on churches, charities, pasty makers and even caravan owners had to be reversed.

His first budget as Chancellor in a Conservative majority government last year had as its centrepiece an attack on tax credits that had to be hastily scrapped in the face of a Parliamentary rebellion led by his own MPs. But the 2016 Budget may prove to be Osborne's nadir because it has demonstrated beyond doubt that he places his own political interests ahead of the national interest. He was determined to please Tory MPs by cutting taxes, even when the country can't afford it, and despite the fact it means the UK is now less well-placed to weather a global recession should one arrive.

The Office of Budget Responsibility has said he only has a 50% chance of achieving his stated aim of creating a budget surplus by 2020, and warned of more austerity ahead. The Institute of Fiscal Studies called his budget "disingenuous" and attacked his "rhetorical nonsense". Jeremy Corbyn summarised the budget perfectly when he told the House of Commons it had "unfairness at its very core".

We now know that's a description even Iain Duncan Smith agrees with. George Osborne's lifelong ambition of becoming Prime Minister is now disintegrating before his eyes because of a political miscalculation of epic proportions. How long before his Tory colleagues decide to put the country before their Chancellor's career and boot George Osborne out of the Government?

Tom Watson is deputy leader of the Labour Party and MP for West Bromwich East