The demand follows revelations, first reported in The Herald, that Michael Gove asked for “testing of people’s attitudes” around “union-related” issues to be undertaken as part of a contract ruled unlawful by the High Court.
Earlier in June, the High Court ruled a £560,000 contract awarded under emergency Covid-19 laws to market research agency Public First had been unlawful and presented a “real danger” of appearing biased due to its links with former colleagues of Dominic Cummings and Mr Gove.
The same firm, through the contract, was used to undertake union-related research, court documents from the case show, with the office of the Chancellor of the Duchy of Lancaster having made an “urgent request” for research around the union.
SNP deputy leader in Westminster, Kirsten Oswald, called for an inquiry into the “gross misuse” of public money.
A spokesperson for the Cabinet Office rejected claims the contract had been used for party political polling.
Mr Gove’s request was revealed in a witness statement by Catherine Hunt, the head of insight and evaluation for the Prime Minister’s office and the Cabinet Office’s communications team.
In her statement, she claims there was an “element of Covid-19” to the research and Public First could be used “before returning to the procurement”.
She said: “Independently around this time, I also received an urgent request for Union-related research from the office of the Rt Hon Michael Gove MP. In response, I asked Public First to conduct some testing of people's attitudes on this issue.
"There was an element of Covid-19 to this testing which at the time we considered was sufficient to enable us to use the existing contract. I knew that we would need to restart the qualitative agency procurement that we had postponed at the start of the crisis as soon as our workload permitted.
"However, this particular piece of Union research was urgent and had some links to Covid-19 and given that the contract with Public First was in place and it was well within their capabilities, we as a team thought we could use them to start the work before returning to the procurement.”
The SNP’s Kirsten Oswald said the UK Government was “engulfed in cronyism” and called for “full transparency”.
She said: "It is a scandal that in the midst of a deadly pandemic, Tory ministers were misusing emergency COVID-19 contracts for constitutional campaigning instead of saving lives.
"This is a gross misuse of public money and emergency COVID contracts, which existed to tackle the pandemic. There must be an inquiry and those responsible must be held to account."
A Cabinet Office spokesperson said: "Any suggestion that the Government carries out party-political research or polling is entirely false.
"Strengthening the union and levelling up in every part of the UK are government priorities, and we regularly undertake research to support policy development.
“The judgment in this case makes clear that there was no suggestion of actual bias and that the decision to award the contract was not due to any personal or professional connections."