Alex Salmond has ruled out any type of post-election deal between the SNP and Conservatives, in an exclusive interview with the New Statesman.

Speaking to NS editor Jason Cowley, he was unequivocal about what would happen if the Tories tried to form a minority government.

“The Tories would have to go effectively straight for a vote of confidence, usually the Queen’s Speech…and we’d be voting against.” “So if Labour joins us in that pledge, then that’s Cameron locked out.”

Salmond’s intervention comes with just over six weeks until polling day, and confirms that David Cameron has little chance of winning a second term – let alone a third – unless the polls shift.

The Tories are set to win around 280 seats in May. That would be more than 40 seats short of the 323 any party needs to hold a majority and pass a Queen’s Speech. The Lib Dems are likely to only win around 25 to 30 seats; another Tory-Lib Dem coalition will fall short of a majority.

For Cameron to remain in power he will have to form a four-party pact between the Lib Dems, DUP and Ukip. Even then, he will probably fall a few seats short.

If Labour and the SNP vote down a Tory-led government, they will have two weeks to form an alternative. If they don’t, they will trigger a second election. Salmond told the New Statesman that he thinks Labour will therefore strike a deal with the SNP at any cost.

“Under the [Fixed-Term] Parliaments Act, that Westminster's parliament passed but nobody seems to have read, you’d then have a two week period to form another government, and of course you want to form another government because this might be people’s only chance to form another government.”

The key issue in this campaign is now whether there will be an “anti-Tory” majority. If Labour, the SNP, Greens, Plaid Cymru and SDLP together hold more than 323 seats, it is impossible to see how Cameron can survive in Number Ten.

An average of five current election forecasts suggest these five parties would hold 327 seats. Whatever happens, the SNP are intent on toppling the Tories.

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In the interview:

Salmond says that Ed Miliband shouldn’t have ruled out a full-blown coalition with the SNP: “If I were him, I wouldn't have ruled it out.”

Says that Gordon Brown’s intervention saved the Union.

Says that David Cameron announcing his plan for English votes for English laws on the morning after the referendum was a mistake. “I’m going to quote Churchill: because in victory, magnanimity.”

Predicts that Danny Alexander, Chief Secretary to the Treasury, and Labour’s shadow foreign secretary and election co-ordinator Douglas Alexander will lose their seats to the SNP.

Says that the party with the most seats won’t necessarily end up forming the government.

Tells us that that the political figure he most identifies with is Nelson Mandela.

Read the full interview, to be published in our Easter Double Issue, here.