Opposition MSPs have called for an investigation into Nicola Sturgeon’s actions during the Alex Salmond affair to be widened after fresh allegations she misled the Scottish parliament. Four MSPs, from Labour, the Conservatives and the Liberal Democrats, have asked a former prosecutor to investigate new claims from Salmond that Sturgeon broke the ministerial code by failing to disclose how much she knew about an internal inquiry into him. James Hamilton QC, Ireland’s former director of public prosecutions, was appointed in 2019 to investigate whether Sturgeon interfered with a civil service investigation into two allegations of sexual misconduct against Salmond, her predecessor as Scotland’s first minister. Salmond has told Hamilton that Sturgeon’s account to parliament of what she knew and when are “simply untrue”. He alleges she had a series of discussions about his concerns about the inquiry, offered to pass on his concerns and gave him advice on what to do. The four MSPs on a special Holyrood committee set up after a court ruled the government’s handling of that internal inquiry was unlawful, said they believed it was “vital” Salmond’s new allegations are formally investigated under the ministerial code. They have written jointly to John Swinney, the deputy first minister, and to Hamilton arguing the case for his investigation to be broadened. Jackie Baillie, a Labour MSP on the committee, said any minister found to have broken the code must resign. Sturgeon’s account was “at odds with Alex Salmond’s”. “It gets harder to swallow with every twist and turn,” Baillie said. On Sunday, Swinney dismissed Salmond’s allegations as “absolute nonsense” and said Sturgeon would robustly defend herself when she gives evidence to the Holyrood committee. Swinney said Hamilton already had the discretion to expand his inquiry if he saw fit. On Friday Sturgeon’s spokesperson said: “The first minister entirely rejects Mr Salmond’s claims about the ministerial code. “We should always remember that the roots of this issue lie in complaints made by women about Alex Salmond’s behaviour whilst he was first minister, aspects of which he has conceded. It is not surprising therefore that he continues to try to divert focus from that by seeking to malign the reputation of the first minister and by spinning false conspiracy theories. “The first minister is concentrating on fighting the pandemic, stands by what she has said, and will address these matters in full when she appears at committee in the coming weeks.” Sturgeon told Holyrood she was first told by Salmond about the allegations when the pair met at her home in Glasgow in April 2018. She published a list showing three face-to-face meetings and two phone calls with Salmond. In a potential breach of the ministerial code, she also acknowledged she did not tell the Scottish government’s permanent secretary, Lesley Evans, about their contacts until the eve of her second meeting with Salmond, at the Scottish National party conference in Aberdeen in June 2018. Sturgeon failed to tell parliament she had also met Salmond’s former chief of staff, Geoff Aberdein, in her Holyrood office on 29 March. She told MSPs late last year she had forgotten it as it was a fleeting meeting because Aberdein happened to be in parliament. Salmond has told Hamilton that is wrong. He said the meeting was arranged after Sturgeon’s chief of staff, Liz Lloyd, had contacted Aberdein earlier that month and had told him about the investigation. Salmond alleges Lloyd also named one of the two women who had lodged complaints against him. The Scottish government said this was untrue. “This meeting was for the purpose of discussing the complaints and thereafter arranging a direct meeting between myself and the first minister,” Salmond told Hamilton. “There was never the slightest doubt what the meeting was about. Any suggestion by the first minister to the Scottish parliament that the meeting was ‘fleeting or opportunistic’ is simply untrue.” Salmond also alleges Sturgeon promised at their first meeting on 2 April she would tell the civil service they had met and pass on his request the harassment complaints be dealt with by mediation. Salmond said that in an exchange of messages on 1 June, Sturgeon had retracted that and instead told him she had always argued her intervention “was not the right thing to do”. “That was both untrue and disturbing,” Salmond told Hamilton.