A month ago we reported that Lucy Frazer had won the South East Cambridgeshire Open Primary.

There was some surprise at the time that Heidi Allen, a businesswoman who had been working the seat hard and was widely tipped as the favourite, had been pipped to the post – but ConHome commenters who were in the room put that down to an “off day” on her part.

Now, though, the result has been thrown into doubt. The Cambridge News reports concerns that there are allegations of a mistake in the count, reportedly discovered by “an activist who took the ballot papers home from the primary decided to recount them”.

The gist of the claims is that a pile of 25 ballots was mistakenly allocated to Frazer when in fact all but the top two votes were for Allen. With the final result coming in at 84 for Frazer and 48 for Allen, those 23 votes would be enough to change the result.

The difficulty in proving the claim is that the ballot papers were taken home before the person claims to have discovered the error. Had there been a recount on the night, it would have been a demonstrable mistake. Instead, the papers have been out of official supervision and in the hands of one person, which – while there are no allegations of wrongdoing that I can find – means this recount is unofficial.

It’s very important to note that this is no reflection on the Open Primary system; if the alleged error happened it’s a major mistake in a small count and a serious failure on the part of the returning officers, but it could have happened under any selection process.

The Cambridge News reports that Heidi Allen received 60 votes in the first two rounds of the primary, which does make it surprising that 12 of her voters would then abandon her in the final runoff – though it’s not impossible that tactical voting could have played a part.

The Association will meet on Friday, in the presence of Paul Mabbutt, the National Nominating Officer and Gareth Fox, the Conservative Party Head of Candidates, to consider what to do next.

Stuck in the middle of all this, of course, are the two would-be MPs and the voters of South East Cambridgeshire, all of whom are now in a horrible situation. It’s in all their interests that the matter is resolved swiftly, cleanly and publicly – which could very well mean a rerun of the Open Primary.