SCOTTISH Labour today launches its own campaign to keep Scotland in the United Kingdom, insisting its distinctive voice will be used to argue there is a better future if Britain's talents and resources are shared to unite behind common causes.

Gordon Brown, the former prime minister, who has largely kept out of the public eye since leaving Downing Street in 2010, will join Scottish Labour leader Johann Lamont and her deputy Anas Sarwar to launch United with Labour.

Speaking ahead of today's event in Glasgow, Mr Sarwar said: "In the debate over the coming months there will be a number of voices all making the case for Scotland working together as part of the United Kingdom. But one voice that must be heard is the Labour voice and I am determined that in this campaign it will be heard."

The Glasgow MP insisted Scotland was now at a crossroads with "two futures" before it.

"One in which we choose to share our talents and pool our resources with others. A future where we unite behind common causes. A future where we work every day to dismantle barriers to opportunity and success. A future where in the country we are proud to call home, we stand by and work for a set of values. A future where we achieve more together than we ever could alone."

He said Labour's campaign would complement the Better Together's providing a "distinct Labour voice". He added: "Just as we recognise Better Together has a job to do, we also recognise its job comes to an end after polling day; Labour's job goes on."

The deputy leader also revealed the party would hold a series of anti-independence roadshows across Scotland with the first tonight in Fife, attended by Mr Brown and 400 people.

He made clear Ed Miliband, the Labour leader, would attend at least one of these roadshows, which will continue up to polling day in September 2014.

While Mr Brown was unavailable for comment yesterday, it was suggested in his contribution at today's launch he will argue a vote to leave the UK would result in abandoning Labour colleagues in England to years of Conservative governments.

Consequently, a vote against Scottish independence would help keep the Tories out of power at Westminster, which would in turn benefit Scotland.

This argument was last night seized upon by Alex Salmond, who branded it "political, arithmetical and intellectual nonsense".

Speaking at a Yes campaign event in Glasgow, the First Minister said: "Mr Brown used to argue against independence because of the social union with the rest of the UK, but the social union stays with independence.

"He is now arguing against independence on the basis of the political union, but it is this political union that has clearly failed Scotland on any measure and needs to be replaced with a new relationship of equality between the nations of these islands."

Mr Salmond suggested the line attributed to the former premier was political nonsense because Labour could not credibly call on Scotland to save England from the Tories while being in the same anti-independence campaign as them.

It was arithmetical nonsense because Scotland had had 30 years of Tory governments "being imposed on Scotland by Westminster" and for only 26 months during this period had Scottish MPs made any difference in terms of electing Labour; every other Labour government would have been elected south of the Border anyway, he said.

It was intellectual nonsense because nations were entitled to choose their own governments.

"What Scotland can do with the powers of independence is be a beacon for progressive policies to deliver a fairer society and stronger economy," the First Minister added.