Private Whatsapp messages between Nicola Sturgeon and Alex Salmond will be made public today as part of an investigation into the Scottish Government’s unlawful pursuit of the former First Minister.

A tranche of evidence will be published by the Holyrood inquiry into the botched process, which cost the taxpayer more than £600,000 in legal fees.

The publication will include Sturgeon’s submission, which is understood to contain the text exchanges as well as her account of meetings with Salmond about the case.

Part of the Holyrood committee’s remit is to investigate “actions taken in relation to the Scottish ministerial code”, focusing on whether Sturgeon misled MSPs with statements she made about contact with Salmond.

The First Minister told parliament that the first she knew of the Government inquiry into allegations of sexual misconduct against Salmond was when he visited her home in Glasgow on April 2, 2018, accompanied by Geoff Aberdein, his former chief of staff, and Duncan Hamilton, his solicitor.

However, on March 29, 2018 Aberdein had met Sturgeon in her Holyrood office where, according to a statement made before Salmond’s trial, the investigation was discussed. It is against parliamentary regulations to carry out party business at Holyrood and the First Minister denies this account of the meeting.

Sturgeon and Salmond met at the 2018 SNP conference in Aberdeen on June 7 and again at her home on July 14. They also had two telephone conversations, on April 23 and July 18.

Sturgeon has insisted the meetings with Salmond were carried out in her capacity as leader of the SNP.

Submissions from Peter Murrell, the SNP chief executive who is married to Sturgeon, and Liz Lloyd, the First Minister’s chief of staff, will also be published by the Holyrood committee. It is understood that in Murrell’s submission he admits sending Whatsapp messages that appear to show him supporting pressure being put on police to pursue their criminal investigation of Salmond. The former First Minister was acquitted of all charges at his trial.

The Holyrood inquiry is examining the Government’s botched handling of complaints against Salmond, which resulted in him being awarded £512,000 in costs after it was ruled that the process was unfair and tainted by apparent bias. The Scottish Government spent a further £118,000 on advice from a QC.