His comments came after Mr Salmond predicted England would be “dancing to a Scottish tune” if the election delivers a hung Parliament with SNP MPs holding the balance of power.

But Mr Cameron insisted the only options for voters casting their ballot in any part of the UK was between continued Labour rule and a switch to Conservative government.

Asked about Mr Salmond’s comments at his regular press conference in London, Mr Cameron said: “The reason he is making these noises is that he knows that he is actually quite irrelevant in a UK general election.

“People in Scotland will be going to the polls to vote for a British Government and there are two potential outcomes: Gordon Brown and Labour continuing in office or the Conservatives bringing the change the UK needs to see.

“The one outcome there can’t be in a British general election is an SNP government.

“Alex Salmond isn’t even standing in this election, so he knows he is quite irrelevant in this election.

“He is battling for relevance and trying to say that somehow he is going to have a pivotal role when it is not an election that even involves him. That is why he is saying what he is saying.

“What we will be doing is putting across to Scottish people all the arguments why the British government, the UK government, needs to change direction when this election is held.”