THE SNP will "call the tune" at Westminster after the next election, Alex Salmond will tell supporters at a meeting to confirm his candidacy in Gordon.

The former First Minister will demand "progress" towards reducing austerity, scrapping nuclear weapons and delivering new powers for Holyrood as his party's price for supporting a Labour government.

He is expected to tell activists at his adoption meeting in Insch: "It is now clear that neither Tory or Labour will win an overall majority. Neither are fit to govern.

"It is also clear that Scotland is swinging behind SNP candidates the length and breadth of the country. In that situation Scotland can call the tune in the next Westminster Parliament."

He will add: "We cannot give any support formal or informal to the Tories because of their track record of hostility to Scottish interests and the total bad faith of David Cameron towards the Scottish people the day after the referendum.

"However, support for any other administration comes with the condition of progress for Scotland.

"This is an exciting moment for Scotland - an opportunity of real change for the better. In conjunction with our allies in Wales and in the English Greens we can form a progressive alliance to shake Westminster to its foundations, to rumble up the House of Common and to make real progress for Scotland."