David Cameron has launched a blistering assault on the European Commission after walking into a summit confrontation with Brussels over the UK's budget that has battered his hopes of combatting Ukip and infuriated his Eurosceptic MPs.
In a piece of timing that could have been designed to undermine the prime minister and hand Ukip leader Nigel Farage a propaganda advantage ahead of the Rochester by-election, Cameron was handed a £1.7bn bill from the outgoing European Commission.
Apparently taken by surprise, the prime minister immediately halted proceedings to demand, and get, an emergency meeting of EU finance ministers to review the demand.
And he was joined by other parties in branding the move "unacceptable" and insisting it could not stand.
As the summit ended, a furious and red-faced Cameron said "there was no way" he would pay the bill by the 1 December deadline, adding: "If people think I am, then they have got another thing coming. This is not happening."
In an unprecedented attack on the Commission, he told a press conference there had been "downright anger" at the "completely unjustified and sudden production of a bill for Britain. This is not acceptable, it is an apalling way to behave."
Thumping the lectern, he also quoted words from the Italian premier that "this isn't a figure, it is a lethal weapon" adding there was the impression the EU was full of "technocrats and bureaucrats without a soul and I agree with every word of it".
But, while the prime minister and his MPs were clearly furious at what some claimed was an "ambush", Chancellor George Osborne confirmed the UK had been informed about the move days ago.
And that led to claims the prime minister had been hoping the issue could have been kept under the carpet until after next month's vital Rochester by-election, painfully aware of the damage it could do to his hopes of stopping a potentially devastating victory by Ukip.
Cameron dismissed that as a red herring saying: "you don't neeed to have a Cluedo set to know somebody has been clubbed by a lead pipe in the library."
As it is, Farage has seized on the row, branding the demand "outrageous" pressing home his claim it proves Cameron is powerless in the face of the EU.
Shadow Chancellor Ed Balls branded the demand unacceptable and also questioned why it appeared to have come as a surprise.
And Britain's former US ambassador, Sir Christopher Meyer, said the timing was a deliberate provocation by the Commission, which loathed the UK.
Meanwhile leading Eurosceptic MPs, led by former minister John Redwood, are urging Cameron to simply refuse to pay the bill and challenge to Commission to do their worst.
The technical measure is a result of the annual recalculation of individual states' contributions to the EU budget with the UK's recovery meaning it automatically needs to pay more into the pot.
The fact that struggling Greece, for example, is among those facing demands for more while France and Germany are getting rebates has only added to the anger and dismay at the Commission's action.
And the fact that Brussels has taken no account of the political impact of the demands, which is not part of its remit, has added to the exasperation in Downing Street and in the Tory party.
The agreement to hold a future finance ministers' meeting will be seen as a limited victory for Cameron as it suggests the political impact of the measure will now be fed into the calculations and get him off the hook.
And there is a real possibility he will be able to find support from states in a similar position, including Greece, Italy and the Netherlands.
It is even conceivable that, on this occasion, the Commission has overstepped the mark and the new Commission, headed by Jean-Claude Juncker, which takes over next month, will be moved to re-think the proposal. But Juncker pointed out Cameron had signed up to the mechanism and the UK had provided the data for the calculations leading to the demand.
Howeve, even if Cameron succeeds in winning changes, it will do nothing to undo the damage already done to the prime minister's credibility over Europe, or head off the inevitable attacks from Ukip and even his own Eurosceptic MPs.
Once again he appears to have been directly challenged by Brussels and found himself fighting a rear-guard action against the Commission while desperately looking for friends.
And Farage's grin just gets wider by the day.