The Conservatives threatened Mr Swinney with the vote last week after his initial refusal to release legal guidance that the Scottish government received while conducting their investigation into former first minister, Alex Salmond.
Mr Swinney ultimately agreed to release the guidance, but the leader of the Scottish Conservatives, Douglas Ross, confirmed on Sunday that his party would press for the vote regardless, subject to a decision by the parliamentary bureau, and alleged that the documents “contradicted” earlier claims that the government did not ignore the advice they received.
Mr Ross said: “John Swinney’s position has become untenable. He has disrespected the Scottish parliament repeatedly, blatantly withheld evidence from a parliamentary inquiry and tried to mislead the public.
“He has had more than enough chances to be transparent, but his actions are getting more murkier and inexcusable as the weeks go on.”
Mr Salmond claimed that the Scottish government was warned by its lawyers that their case would fail before this was publicly conceded, and that Nicola Sturgeon broke the ministerial code by not abandoning the challenge.
According to the documents, the lawyers advised the government that the challenge “was capable of being resisted successfully”, but that there was a “real risk that the court may be persuaded by the petitioner’s case in respect of the ground of challenge based on ‘procedural unfairness’”.
In December 2018, lawyers said that the “least worst option” for the government would be to concede the petition. They did not do so until the following month.
Mr Salmond received a payout of more than £500,000 after a court ruled that parts of the Scottish government’s investigation into his conduct were carried out unlawfully.
The Scottish National Party (SNP) accepted the ruling but strongly maintained that there was never a plot against Mr Salmond, with Ms Sturgeon telling the Holyrood inquiry that the suggestion – made by her former friend and predecessor as first minister – was “absurd”.
The SNP have been contacted for comment.