The SNP has denied it secretly wants Britain to leave the European Union - a move that would almost undoubtedly lead to a second referendum on Scottish independence.
Patrick Grady, MP for Glasgow North, insisted his party would campaign fiercely for a Yes vote when David Cameron calls the EU referendum.
And speaking as the EU Referendum Bill was introduced into the House of Commons, Alex Salmond said it was "deeply insulting" to exclude 16 and 17-year-olds from having a say in the vote - a view backed by MPs on all sides of the House.
Responding to suggestions the SNP would secretly favour a No vote so Scotland would be granted independence through the back door, Mr Grady told the World at One: "The SNP will be campaigning very strongly for a positive Yes vote for the European Union.
"We think that membership of the European Union for Scotland and the United Kingdom as a whole bring tremendous social and economic benefits and we want to be a positive contributor to the Yes campaign to make a positive case for remaining within the European Union."
Mr Salmond, the SNP's foreign affairs spokesman, also suggested the government's decision to exclude most non-British EU nationals from the vote would fail a challenge in the courts.
He said: "It's not the case that all other European citizens are to be a denied a vote in this referendum.
"Citizens of the Irish Republic will have a vote in this referendum, citizens of Malta, of Cyprus will have a vote in this referendum because of the Commonwealth entitlement.
"How can you have an argument that says some other European citizens will vote but some others will not?"
Mr Salmond added: "When you propose a referendum it should be because you are proposing a change, you are proposing a significant constitutional change, whether it be for the alternative vote, or Scottish independence, or Scottish devolution or Welsh devolution, you are proposing a change and you are looking for democratic sanction, the sovereignty of the people to back your change.
"But that is not the position of the Prime Minister, nobody seriously believes that the Prime Minister wants to take this country out of the European Union, the referendum is a tactic.
"A tactic that is being deployed as a means of deflecting support from Ukip, as a sop to the backbenchers, nobody actually believes the Prime Minister wants to take the country out of the European Union.
"And the suspicion that we are already seeing developing in this debate is as the result of that essential contradiction and the Government's proposition."Reuse content