So, William Hague knew some months ago that Milord Ashcroft had not stuck to the spirit of his assurances, but only let Dave know about it within the last month. Lord Ashcroft has misled at least two Tory leaders - Iain Duncan Smith wasn't there long enough to matter - about his tax status. He promised to become a permanent resident - which should have been enough in the eyes of the Revenue for him to be domiciled in the UK for tax purposes - but didn't.
Hague and Brown don't come out of this well. Either neither felt brave enough to challenge Lord Cashpoint over his tax status or they knew the truth - even in a plausibly deniable way - and chose to ignore it.
Ashcroft has to go, despite his status as a foul-weather friend who has now magnetically attracted fresh storms to the party. His continued presence at the heart of the party is hamstringing the campaign - Conservatives have made themselves unavailable to discuss the matter and this prevents them from making key statements on policy, as they are bound to be asked about Ashcroft. They are hoping that this will all blow over, but I'm not so sure that it is done. Both the Liberal Democrats and Labour have an interest in prolonging this row and they are milking it for all they can, as it really speaks to the heart of the Conservative party and how much they really represent change.
It was very interesting and perhaps a signal of a battle yet to come that tonight's Question Time saw the blonde bombshell, Boris Johnson, distancing himself from Lord Cashcroft - perhaps positioning himself ready to replace Dave.
Remember, unlike other non-dom donors, Ashcroft has a central role in the party, directing strategy in the marginal seats. Ashcroft is the only non-dom who made a promise to their party leader to take up permanent residence and has failed to do so. Ashcroft only 'spoke out' about his tax status when he was forced to by the imminent release of information under the Freedom of Information Act.
Meanwhile, a very important poll in the key marginal seats - the ones that would deliver a Tory majority - showed that their lead had dwindled over 18 months from a 13 point lead to just 6.5% this month, running some two points ahead of the national swing. This leaves the Tories the largest party, but 11 short of a majority. It seems that the Ashcroft money isn't buying the votes as easily as you would think.