Nicola Sturgeon has opened up fresh questions over the legitimacy of the next government if the General Election produces a hung parliament.
Speaking on the campaign trail in Dumfries on Sunday the first minister said a government that did not reflect the choice of the Scottish electorate would not be legitimate.
"Surely a test of legitimacy that should be applied to whatever Westminster government is formed after this election cannot simply be that it is the largest party in England," said Sturgeon.
"The test that must be applied is whether a government can build a majority and win support that reflects the whole of the UK. English MPs will always be the largest part of any Westminster majority, but to ignore Scottish voices would be wrong," she added.
The SNP has said they would be willing to work with Labour to keep the Conservatives out of Downing Street. But she added that Ed Miliband wouldn't be given a "free pass" to govern with SNP support. Sturgeon said she would press Labour to change its plans of public spending to ease further austerity.
Under intense pressure from the Conservatives, the Labour leader has ruled out any deals or coalitions with the SNP. However, it remains unclear whether the parties would work together on a vote by vote to form an anti-Tory majority in the House of Commons.
The First Minister said yesterday: “If there is an anti-Tory majority on Friday morning, we will call on Labour - even if they are not the largest party - to vote with us to keep the Tories out.
The implication of Sturgeon's remarks is that if the Tories manage to win the most seats in England but the SNP sweep the board in Scotland there would be serious questions over the government's legitimacy.
The story comes as the SNP's deputy leader Stuart Hosie failed to rule out another independence referendum if Scotland doesn't get a better deal from Westminster.