The SNP leader warned in a speech to the party’s annual conference that politicans who oppose an independence referendum could suffer at the ballot box.

Mr Salmond said the event in Inverness was a launch-pad for success in the Glasgow North East by-election and the General Election, which is widely expected to be held next spring.

He said: “In our 75-year history we've never been closer than we are now to our objective of national independence for our nation."

“Do parties in Scotland really believe that the people of Scotland will give them their vote if they refuse to give the people of Scotland a vote on the constitutional future of the country."

He recalled how 25 years ago many people thought Scotland would never have its own Parliament, but added that had been achieved 10 years ago.

Mr Salmond also said that even five years ago "most informed opinion" was that the SNP would not be able to form the Scottish Government.

He added: “Most informed opinion said we couldn't possibly manage that, it was beyond the scope of the SNP to make that sort of advance in a single election campaign," the First Minister said.

"But in 2007 the SNP became the Government of Scotland."

He added that stage three of Scotland's journey as a nation would be "going from that platform of a devolved Parliament, that platform of a Government in that Parliament, to achieving national independence".

Mr Salmond also said the conference would be a "launch pad" for the Glasgow North East by-election and for the General Election.

He said: "In that election our objective is clear - we're going to make Scotland's voice heard. We're going to see a platform, a Scottish block of at least 20 Scottish National Party MPs.

"If we obtain that then Scotland's voice will not only be heard but Scotland's demands will be answered."

The leader also hit out at the Westminster Government for failing to allow an SNP minister to be part of a crucial climate change summit in December.

He said Scotland had passed climate change legislation which was "not just world leading but potentially planet saving".

He argued it was an "incredibly reasonable request" for the Scottish Government to have a minister at the Copenhagen summit.

However, Mr Salmond said Prime Minister Gordon Brown had refused this. He said: "Only yesterday the Prime Minister wrote me a letter. `Dear Alex, he said, no he said`."

Mr Brown's letter to the First Minister stated that "Scotland - as part of the United Kingdom - will be represented ministerially by Ed Miliband" the UK Climate Change Secretary.

But Mr Salmond added: "The Parliament, the Government, the people, the nation, who passed the most ambitious climate change legislation in the world are to be denied a direct voice at the Copenhagen summit in December, which is going to discuss the legislative steps which are necessary across the world in order to face one of the greatest threats to human kind."