IAIN DUNCAN SMITH sent shockwaves through Westminster last night after resigning his position as Work and Pensions Secretary over disagreements with George Osborne's budget.
Mr Duncan Smith, a former Conservative party leader, wrote of cuts to the benefits of disabled people to be "a compromise too far" when set against the desire for the country to balance the books.
He added: "While they are defensible in narrow terms, given the continuing deficit, they are not defensible in the way they were placed within a budget that benefits higher earning taxpayers."
Here, Mr Duncan Smith refers to the increase in the starting point of the 40% tax band from £42,385 now to £45,000 in April 2017.
That was a move by Mr Osborne which was generally well received as, along with the increase in the personal allowance to £11,500 next April, it helps many workers in middle England.
Moreover, fuel duty was frozen for a sixth year in a row - while beer, cider and spirit duties were also frozen.
Yet, despite these little pick-me-ups, the overall impression of the budget this year was unquestionably negative.
No doubt to some extent that was down to Mr Osborne himself. Growth forecasts were revised downwards markedly for the next five years while borrowing was revised upwards.
Mr Osborne also admitted he would miss his target of reducing debt as a share of GDP - one of his three golden rules - but declared public finances were still projected to achieve a £10.4bn surplus in 2019/20.
That can only be achieved by making a further £3.5bn-worth of cuts by 2020, some of which were projected to fall upon the disabled.
Consequently, the budget was not only perceived as being negative, it was also considered to be unfair in a poll by a margin of 38%-28%.
Only 13% of people support the disability cuts while 70% think they are the wrong priority at the present time, including 59% of Tory voters.
In fact, this is the first budget which has been considered more unfair than fair since the "omnishambles" of 2012 - and Mr Osborne's personal ratings had already taken a hit even before Mr Duncan Smith's decision.
Prime Minister David Cameron, meanwhile, has said he is "puzzled and disappointed" that Mr Duncan Smith has resigned.
He added: "While we are on different sides in the vital debate about the future of Britain's relations with Europe, the Government will, of course, continue with its policy of welfare reform."
Ah yes, Europe. The issue which has divided - and, at times, torn apart - the Tory party for over 30 years has been dragged to the forefront of the political arena with the referendum date set for 23 June.
London mayor Boris Johnson has already made a calculated move by putting himself on the side of Leave. Would it be too cynical to suggest Mr Duncan Smith, another in favour of Brexit, is trying a similar tactic?
Perhaps it would not. After all, Mr Duncan Smith did not seem too concerned about welfare reform - i.e. cuts - when he celebrated wildly in the House of Commons last summer.
Instead, this decision to depart the Cabinet allows the MP for Chingford and Woodford Green to campaign more vigorously against Mr Cameron and Mr Osborne in the run-up to the referendum.
A rivalry with Mr Osborne, in particular, exists ever since the Chancellor is said to have described Mr Duncan Smith as "not clever enough".
But, whether that is true or not, this perceived scheming is doing little to give the impression that this Conservative government has the best interests of the country - rather than itself - at heart.
Labour leader Jeremy Corbyn has this morning called directly on Mr Osborne to follow Mr Duncan Smith by resigning.
Mr Corbyn cited "a Government in disarray and a Chancellor who has lost the credibility to manage the economy in the interests of the majority of our people" while imploring again that "the Government must change economic course".
That, of course, seems unlikely - but the biggest worry for Mr Osborne may be the Government's wafer-thin majority.
Having already been forced into a U-turn over cuts to tax credits last year, the Chancellor faces a group of several Conservative MPs who have written a letter threatening to rebel again.
Either way, Mr Osborne's budget plans are now in a total mess - full of missed targets, broken golden rules and, worst of all, an attack on some of the most vulnerable in society.
It has taken a while to come to this - but the great British shapeshifter has finally started to become unmasked.
Earlier Budget reports from Mr Osborne 2011 2012 2013 2014 2015(March)
