Can Carswell kipper the Commons?
The King of Clacton is now the Keir Hardie of the 'kippers.
Douglas Carswell will re-join the House of Commons next week, and add to its small band of one person parties (alongside Dr Caroline Lucas for the Greens, Naomi Long for the Alliance Party and George Galloway for Respect).
One immediate question is which two MPs will stand by him as he is introduced to the House…technically an MP can't take their seat without two supporters at this ceremony, but that's a very technical technicality.
So will Mr Carswell be supported by friends from his former party or have to rely on teeth-gritting "supporters" drafted by the whips?
I suspect it will be the former; there's a big contingent of "unite the right" Tory MPs who think the right approach to UKIP is to show it, and its voters, respect.
But that is just the first manifestation of a bigger question: how will Mr Carswell be greeted by his ex-colleagues? I suspect his fellow UKIP defector, Mark Reckless, will have a tougher time if he makes it back to the Commons - Tory MPs were infuriated by his defection on the eve of their conference, and will find him much harder to forgive.
But the key point is that Mr Carswell gives UKIP a voice in the Commons - and his task now will be to use that voice. I don't think he will be bound by the normal convention of making an uncontroversial maiden speech - although he would have little trouble praising the work of his predecessor (ie himself).
Next week's agenda provides several speaking opportunities, and he may seek to take them all: the post-Scotland debate on Tuesday allows him to push UKIP's view on English Votes for English Laws; then there's the possibility of being called at Wednesday's PMQs (David Cameron's response would be interesting indeed) and on Friday there's the second reading debate on the bill for an EU Referendum.
Not that long ago, Mr Carswell's view was that he didn't want to rock the Tory boat, now the party was committed to a referendum; his decision to leave the Conservatives seemed to crystallize when he lost faith in the line Mr Cameron would take in a referendum campaign, so we might hear more about that - and he might take the chance to taunt the Tory leadership.
They in turn will be combing his considerable volume of writing to find some political tripwires.
Just as interesting will be Mr Carswell's approach to Labour, and Labour's approach to him. Labour's near-death experience in Heywood and Middleton has certainly shaken MPs from similar constituencies, but I'm not sure the party really knows how to respond.
There will now be a lot of pressure to find an answer, and fast - Ed Miliband addresses the Parliamentary Labour Party on Monday, and he will doubtless face an uncomfortable time.
Mr Carswell is a highly effective parliamentary guerrilla, and he doesn't lack guts. It was he who led the uprising which toppled Speaker Martin from the Chair, when more cautious souls kept their heads below the parapet.
But in an era where message politics is crucial, his task on behalf of his new party will be to strike a different note as often as possible.
A good role model for this is the Greens' Caroline Lucas. She doesn't seem to have any special deal from Mr Speaker, as the sole voice of a national party - she's been called 10 times in PMQs in this Parliament, for example, which seems about average. But she normally does get in during big ministerial statements and she has been effective at putting a distinctive Green position.
It won't be easy, though, to make the switch from being a footsoldier in a big party, with whips and supportive colleagues on hand, to being a lone wolf in the Westminster fold - with no support structures, and old friends loath to be seen gossiping with you in the Tea Room, or plotting in Portcullis House.
But his performance in keeping the UKIP flag flying will have a big bearing on the next election.