THE SNP will block any attempt by the Conservatives to form a minority government if they hold the power, Alex Salmond has said.

In an announcement which will come as a blow to the “vote SNP, get Tory” Labour campaign slogan, Salmond confirmed SNP MPs would vote down any Conservative Queen’s Speech.

The former First Minister said this would allow Labour to have the chance to form a minority government, with the votes of the SNP on a confidence-and-supply basis.

The news comes in contradiction to repeated claims from Scottish Labour leader Jim Murphy that the largest party automatically gets to form the government if no majority is achieved.

The SNP candidate rejected this argument, calling on Labour to join the SNP in a pledge to stop the Tories serving a second term in government.

“The Tories would have to go straight effectively for a vote of confidence, usually the Queen’s Speech, although it could be otherwise, of course, and we’d be voting against,” Salmond said.

“So if Labour joins us in that pledge, then that’s Cameron locked out. And then under the (Fixed-Term) Parliaments Act that the Westminster Parliament has 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 SNP could then enter a “confidence and supply” arrangement with Labour, offering support on a vote-by-vote basis, and making amendments to any budget put forward by Ed Balls to introduce “progressive tax measures”, Salmond explained.

The announcement will also go some way to dispelling claims from Ed Miliband on Monday that there is an “unholy alliance between the Conservative Party and the SNP to carry on a Tory government”.

First Minister Nicola Sturgeon has already repeatedly confirmed the SNP will not prop up a Conservative government in any way and yesterday’s announcement will further entrench their opposition to David Cameron’s party.

If polls are to be believed and the SNP are able to deliver over 40 MPs to Westminster while both the Labour and Conservatives remain within a small number of seats of each other, the SNP, alongside other smaller parties, will have the deciding voice in who gets into power.

Research suggests this is by far the most likely outcome, with both the main Westminster parties unlikely to gain a majority.

Of the announcement, a Conservative party spokesperson said this arrangement could endanger the future of the Trident submarine and would mean “chaos” for Britain.

The spokesperson said: “Alex Salmond has confirmed he would sabotage the democratic will of the British people to make Ed Miliband prime minister.”

“That would mean chaos for Britain, with weak Ed Miliband dancing to Alex Salmond’s tune.”