Former cabinet member and senior figure in the SNP, Alex Neil, made the claim that legal action could help bring down Theresa May as well as showing that the deal breaches the Barnett formula.
The formula measures how to fairly share out money across the UK’s devolved administrations.
According to the SNP, the Scottish Government should receive just under £3 billion as a result of the deal struck with the DUP.
According to Mr Neil, the First Minister should now seek to take legal action over the deal on the basis that it has left Scotland disadvantaged.
The Scottish Government has already threatened a formal dispite over the issue through the Joint Ministerial Commission.
Speaking about a formal dispute, Alex Neil said: “That takes time I think there’s a quicker way to pursue it through the courts.
“I think they have breached a fundamental part of the financial settlement and I think they have breached the principles of the fiscal framework.
“If we won that legal case I think it would force Theresa May out of Downing Street.
“What a tremendous blow for freedom that would be.
“It would show how rotten the Union is under the Tories.”
He added: “To sue them for the £2.9bn, even if it’s not successful, would show how rotten this deal is for Scotland and how the Tories have sold us down the river.
“They’ve broken the Barnett formula and have betrayed the people of Scotland. They have done us out of £2.9bn.”
Following the comments made by Mr Neil, a UK Government spokeswoman said: “The UK Government has the power to provide funding outside Barnett - such as investing nearly £700 million in UK City Deals in Scotland.”