The SNP Westminster leader has again demanded answers over the use of emergency Covid contracts.
Granted an urgent question in the Commons on Tuesday, Mr Blackford called for an independent investigation into “blatant misuse of public money for political purposes”.
He said: “After the revelations and resignations at the weekend, this urgent question concerns yet another scandal at the heart of this Tory government.
“Not even a health pandemic can do away with classic Tory cronyism.
“The Secretary of State ordered the use of a £560,000 Covid emergency contract to conduct constitutional polling on the Union.
“Instead of using an emergency Covid contract to order PPE [personal protective equipment] for the NHS, the minister chose to order political polling.
“This isn’t media speculation and it isn't political, it is plain fact.
“It comes directly from official evidence that has been published in the High Court.
“Did the Prime Minister know or approve of this polling on 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?
“The truth and this government are distant strangers, which should come as no surprise when the Prime Minister has 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 his remarks.
Responding, Cabinet Office parliamentary secretary Julia Lopez insisted context was important to the decision.
She said: “In March 2020 there was no vaccine, no test and trace and very little knowledge on how to best manage this disease.
"Strong messaging of the kind that could alter behaviours was at the outset of the pandemic was one of the few tools in our arsenal in the battle against transmission.
"It was in this context that rapid decisions were made on comms contracts.
“This contract did not relate to constitutional campaigning and any suggestion that the government carries out party political research is entirely false.”