Your SNP Leader (the lady one) has categorically stated on many occasions that any future independence referendum will not be called for by the SNP, but by the people of Scotland itself.
I was under the impression that the last "one in a lifetime" one was decided upon under A. Salmond as SNP leader.
The promise to hold a referendum was in the SNP manifesto for the 2011 Holyrood election, so people voted for it. And Salmond and the SNP kept that manifesto promise.
There would need to be a similar commitment in the 2016 manifesto for the Holyrood election, followed by the election of an SNP majority government. There will only be a referendum commitment in the manifesto when the SNP are pretty sure YES can win it convincingly next time round.
So the process would be:a)
The people of Scotland indicate there is a general mood in the country (via opinion polls etc) for a second referendum AND
indicate that YES is the likely outcomeb)
the SNP, picking up on this, include it in their manifestoc)
The people of Scotland vote overwhelmingly for the SNP - a party that has a commitment to hold a referendum in its manifesto.
The critical part is, what would trigger a)