There seemed something a little contrived about the brouhaha that engulfed Nicola Sturgeon after it was revealed she had provided the wrong date about when she first became aware of complaints about Alex Salmond’s personal conduct. What she had said was shown not to be accurate. But to the uninitiated, the truth, when revealed, did not seem to materially change much.

She told the Scottish parliament that it was on 2 April 2018 that she first became aware that her government was investigating a complaint against her predecessor. That was the occasion in which Salmond visited her house to tell her about it. But testimony from Geoff Aberdein, supported by other sources, demonstrates that she actually first heard about the complaint against Salmond from him in his (then) role as Salmond’s chief of staff in her Holyrood office on 29 March 2018.

Unionists who see the mutual hatred between the current and previous leaders of the SNP as offering a better chance to derail the Nationalist bandwagon than anything they have themselves managed to achieve leapt at the opportunity to play the woman, not the ball. She had said “2 April” but it was really “29 March”! She had not told the truth. She had therefore misled Holyrood – breach of the ministerial code for which the punishment is, potentially, resignation.

However, there is a difference between misleading parliament deliberately and unintentionally. It seemed peculiar that she would not recall the first time she was told something so unsettling about the man she had long described as her political friend and mentor. But it was possible that it had somehow, inexplicably, slipped her mind. There have, after all, been rather a lot of sex pest scandals and harassment allegations in the SNP in recent times and it must be hard to keep up. Nevertheless, the benefit of the doubt could be offered to the busy First Minister. At any rate, what difference does four days make?

Actually, the gap of four days was significant. No record was kept, as it should have been, of the meeting she had at her home with Salmond on 2 April. If that occasion was the first she had heard of the allegations then the failure to do so was understandable. But, of course, if she had already known for some days what the former First Minister would be coming to see her about then the omission to keep a record could be seen as a conscious decision not to play things by the book. Nevertheless, for most Scots, this still remains a procedural infelicity, rather than a resigning issue.

David Davis’s Tuesday evening intervention turns the wrack tighter. Using parliamentary privilege, the former Tory Cabinet minister informed the Commons that an anonymous whistle-blower had sent him transcripts of communications between two civil servants, Barbara Allison and Judith Mackinnon (who was appointed to investigate the complaints made against Salmond). These messages suggested that Liz Lloyd, Sturgeon’s chief of staff, had been intervening in the complaints process against Salmond as early as 6 February 2018. “Liz interference v bad” read one message. Like Sturgeon, Lloyd had claimed under oath not to have knowledge of the Salmond allegations until April that year.

The charitable explanation is that forgetfulness – with side-effects of poor record-keeping and misplacing of key documents – is a contagion affecting many of those who work closest with the First Minister. Is Nicola Sturgeon the Patient Zero of amnesia?

If it is true that her chief of staff was indeed intervening in February 2018, then it represent a rather greater lapse of memory than getting a few days in a muddle. What is more, is it plausible that Sturgeon’s chief of staff was intervening in the Salmond affair for weeks not only without the sanction of her boss but without telling Sturgeon anything whatsoever about it. It is possible. Possible, but remarkable.

Salmond’s allegation that those closest to the First Minister (including her husband) were actively involved in a conspiracy to build a case against him – which, had the criminal court subsequently not acquitted him on all charges, would have silenced him to the jail cell – gains credence the more the lapses of memory and Richard Nixon-level gaps in the official record are revealed. What remains a mystery is why – if they did conspire to bring him down – go to such extraordinary lengths?