Wendy Alexander has "not ruled out" a referendum
Scottish Labour Party leader Wendy Alexander has called on the Scottish Government to "bring on" a referendum on independence.
Signalling a shift from previous comments, Ms Alexander said the SNP should have the "courage of its convictions".
First Minister Alex Salmond said those opposed to the independence referendum were beginning to "crack".
He said the government's referendum bill would be brought forward in 2010.
Ms Alexander's comments followed reports in the Sunday Mail newspaper reports that she and Gordon Brown were "considering" supporting a referendum.
There was also a hint from the convener of the Constitutional Commission, set up by the unionist parties to examine the next steps for devolution, that a referendum may be required.
Sir Kenneth Calman:"It depends on the amount of change (recommended).
"If that change is small, then maybe there would not be any opportunity to do that, but I think it would be up to parliament to decide whether this was a significant enough change to take things further."
As recently as March, Ms Alexander stated her opposition to an independence referendum when she was questioned in a BBC Scotland news website webcast.
On BBC Scotland's Politics Show on Sunday, Ms Alexander seemed to have softened her stance, saying she had not ruled out a referendum.
She said: "Of course, there have been tactical discussions on these issues.
"The SNP appear to be toying with the electorate, saying 'we want this, it is the reason we came into politics, but by the way we are frightened to bring the matter forward'."
She said: "I don't fear the verdict of the Scottish people. Bring it on."
Mr Salmond said: "There's all sorts of indications that perhaps the Calman commission and perhaps the Labour party are trying to rethink their attitude."
He said the referendum bill would be brought before parliament in 2010.
"If there was then this unionist cabal saying 'no, the Scottish people are not entitled to decide their own future', then that would surely become an issue transcending the 2011 election campaign," he said.
"I would woe betide the unionist parties if they stand on a platform of denying the Scottish people self-determination.
"One way or another the Scottish people will decide."
A spokesman for the Conservatives said: "Decisions about Scotland's future should be made after calm and reasonable debate, not as a panicky, nervous, knee-jerk reaction born out of Labour's political disarray.
"That's why the Calman commission has important work to do and it should be left to do it."