The publication of the Scottish Government's consultation paper is a defining moment in a journey of false starts, twists and turns.

When Alex Salmond took over - again - as Scottish National Party (SNP) leader in 2004, he was three years from winning a historic victory, taking charge of the first minority administration in Edinburgh, the home to Scotland's devolved parliament.

The party campaigned in 2007 to secure the "trust and support" of voters, saying the ultimate decision on the constitution would be taken in a referendum.

But the Labour, Conservative and Liberal Democrat parties combined to block any real attempt to put the SNP's first Referendum Bill to the test in the four-year term.

Instead, the opposition groups threw their weight behind a consultation aimed at extending devolved powers - now incorporated in the UK Government's Scotland Bill - but ignored the possibility of independence.

That was left to the SNP in government, which launched its own "national conversation" on the future of the constitution.

What followed were a series of glossy documents outlining the case but, according to the SNP's critics, a lack of detail on the nuts and bolts of independence. Questions are still being asked on what a Scottish army might look like, what currency will be used and how the country would fit in to the EU, if at all.

Along the way, and with the SNP's draft legislation published, the journey took a twist. Wendy Alexander, who was Labour's leader at Holyrood at the time, used a television interview to challenge Mr Salmond to "bring it on" and call a snap referendum with her party's blessing, but not to his timetable.

Mr Salmond refused and put the policy to the people for re-election in 2011 - securing an unprecedented majority in the 129-seat Scottish Parliament, which uses a form of proportional representation. The win means the SNP can pass any legislation without the need to rely on opposition votes.

But calls to bring forward the ballot resurfaced in the high-profile intervention by Prime Minister David Cameron this month. He too told Mr Salmond to hold the ballot sooner rather than later, prompting accusations that London was meddling in Scottish affairs.

Instead, Mr Salmond has stuck to the plan which he alluded to under questioning in a BBC televised election debate last year.

With just days to go to the election, he said the referendum would be held "in the second half" of the current five-year term. There had been no mention of the timescale in the SNP manifesto.

It was only after the UK Government's intervention that he revealed the question would be asked in autumn 2014.

In the past few weeks, the policy has been subject to heightened scrutiny, with interventions on the legal structure to the ballot, what questions should be asked, when it should be held and who should be eligible to vote.

Only when the process is cleared up can the debate swing back to the detailed substance of what independence would really mean for Scotland.