By Jo Coburn
Political correspondent, BBC News
It was a surreal moment, when the rumour whipped round Westminster that David Davis, the shadow home secretary, might be about to resign.
The initial response from journalists was that he had been forced to go because of his comments on Wednesday that the Conservative Party would reverse the 42-day terror detention plans if it were in power.
He obviously hadn't cleared it with leader David Cameron - their relationship has long been strained, one suspects.
It became curiouser and curiouser as it emerged he was not just quitting the shadow cabinet but was going to trigger a by-election in his own constituency on the issue of 42 days.
Why would he do that?
A shared look of confusion and bewilderment spread across everyone. We didn't have long to wait for an explanation.
Mr Davis himself would explain outside the House of Commons; he had intended to make a speech inside the chamber to MPs but the Speaker forbade it.
A growing gaggle of hacks gathered in wait with huge anticipation.
Then, out he came, and made what can only be described as a most bizarre statement justifying his decision.
Nothing to do with his pre-emptive comments (although many still feel that he and Mr Cameron may well have rowed despite the denials by the Tory press office) but in fact Mr Davis was making a personal principled stand.
He said the 42-day law was a "monstrosity" and part of the "government's slow strangulation of fundamental British freedoms".
So he would leave Parliament to fight a noble battle in Haltemprice and Howden, his East Yorkshire constituency, against extending the amount of time terror suspects can be held without charge from 28 to 42 days.
We learned subsequently that the Liberal Democrats would not be putting up a candidate against him and that Labour, who were so delightedly taken aback by the whole episode, still had not decided what to do.
Mr Davis' decision raised many more questions than it answered.
Why would a politician like him, who may well have been home secretary in two years' time, resign when it seems he did not have to, on an issue that may well be defeated in the House of Lords anyway?
Mr Cameron must be privately furious. Everything was going so well - and then this.
An unnecessary by-election on a difficult issue for the Tories.
Possible theories? That Mr Davis has reached a political crossroads, frustrated about the pace of things on issues he is passionate about.
So what to do? Launch a personal crusade and force everyone else in behind you on your terms, pinning your colours - plus that of your party and the Liberal Democrats - to the mast for a later date.
But it is a high-risk strategy that could permanently damage his career and leave him in the political wilderness.
He will no doubt win and generate publicity for himself and his cause, but is that what the Tory leadership wants on an issue that the public are said to be broadly in favour of?
And who would have such a loose cannon in his cabinet? Mr Cameron would be under no obligation to have him back.
Well, who'd have thought - you just couldn't make it up.