The date of the Clacton by-election has been set for 9 October. Douglas Carswell will put himself before his constituents and see whether his decision to jump ship from the Tories to Ukip will be rewarded or punished.
If the polls are anything to go by, Carswell is looking at a landslide victory - the Eurosceptic party will gain its first electoral victory in Westminster.
Such a result would be a bitter disappointment to David Cameron, who has tried to beef up his Eurosceptic credentials by offering an in-out referendum on a renegotiated relationship with the EU in 2017, if the Tories win the election.
What's more, the result will come on the same day as David Cameron's birthday. A Ukip victory could be the Tory leaders' worst birthday present yet.
Mayor of London Boris Johnson ruled out a run for the Essex seat this morning. Speaking to LBC, Johnson said, "The first objection to that, really, is that I've already whacked in the CV for Uxbridge".
This may be just as well. According to a Survation poll for the Mail on Sunday, Boris would lose a contest with Carswell by a country mile. The poll showed Carswell romping home with 60 per cent of the vote while Boris would scoop up just 27 per cent.