SNP Westminster leader Ian Blackford has urged the Cabinet Secretary to launch an independent investigation into “blatant misuse of public money for political purposes”.

Asking an urgent question on the Government’s use of emergency Covid contracts, Mr Blackford said: “Just as the Prime Minister failed to act to sack his health secretary, he has failed to act on this scandal too, but no matter how hard they might try to sweep this under the carpet this scandal isn’t going away.

“This morning I have written to the Cabinet Secretary urging him to launch an independent investigation into this blatant misuse of public money for political purposes…

“If the UK Government has nothing to hide, will the minster join me in supporting this investigation by the cabinet secretary and will she co-operate with it?”

Cabinet Minister Michael Gove has denied allegations of a misuse of public funds from a coronavirus contract used to carry out opinion polling on Scottish independence.

In the Commons, Mr Blackford added: “The truth and this Government are distant strangers and that comes as no surprise when we remember the Prime Minister’s been sacked not once but twice for lying.”

His comments led to an intervention from Commons speaker Sir Lindsay Hoyle, who asked Mr Blackford to withdraw them.

Mr Blackford said: “It seems that not even a health pandemic can do away with classic Tory cronyism and the scale of this particular scandal makes it one of the biggest yet.”

He added: “Did the PM know or approve of this polling and constitutional campaigning? Who were the polling results shared with and will they be published in full?

“How many other pieces of political research were ordered during the pandemic, and exactly how much public money has been spent?”

Cabinet Office minister Julia Lopez told MPs: “How we spend taxpayers’ money matters very deeply to public trust. It’s true to say that the Government faced a number of challenges at the height of the pandemic and I think we should be open about those.”

The minister was challenged by both Plaid Cymru and SNP MPs over the awarding of £500,000 to Public First, in a contract the High Court has deemed “unlawful” and critics said was used to carry out opinion polling on Scottish independence.

The SNP’s Peter Grant (Glenrothes) said there had been a “deliberate misappropriation” of funding for “political canvassing purposes”.

Liz Saville Roberts, parliamentary leader of Plaid Cymru, said: “Let’s call this out for what it is – a gross misuse of public money.”

Ms Lopez replied: “We do not use public money for political campaign purposes.”

The Commons Speaker objected to the line of questioning from a Conservative MP Fay Jones (Brecon and Radnorshire) who asked: “With nothing better to do, the Opposition continues to sensationalise the details surrounding a handful of high value contracts that we subject to the emergency procurement procedures at the outset of the pandemic.

“Can she confirm the Government is committed to transparency surrounding the use of taxpayer money and that all new contracts over £10,000 are published online for anybody who wishes to, to see them?”

Sir Lindsay intervened, saying: “Can I just say, it is my decision to grant the UQ. You are now questioning my judgment and I’m not going to have my judgment questioned.

“The other thing is, I do feel sorry for the minister being set-up. I’m sorry that minister (Michael) Gove wasn’t here to take questions because most of them are named for him, but this House won’t be taken for granted.

“When statements are made outside here, continue to be made, that’s why I’m going to continue to grant UQs, so let’s gets used to it. The Government doesn’t want to come here – I’m going to ensure it is heard here.”