SNP's referendum push

"I can't wait for another referendum," says Kevin Gibney by the banks of Glasgow's River Clyde. The 46-year-old was on the losing side in 2014, but hopes that next time independence will win - if the Scottish Government is actually given the power to hold a second vote on leaving the UK.

Read: UK PM Theresa May rejects call for second Scottish independence referendum

"It all depends on whether Westminster puts its foot down and doesn't let it happen," Gibney, who runs a company called ‘Independence Live' that live streams pro-Scottish nationalist events, told DW.

Westminster has so far appeared unimpressed with the prospect. UK Prime Minister Theresa May on Friday attacked the Scottish government's "divisive and obsessive" pursuit of a referendum. She needs a united Britain as she prepares to trigger its withdrawal from the European Union.

For now, however, many Scottish nationalists are pleased that the question of a second independence vote is back on the table. Sturgeon's keynote address this weekend is expected to flesh out the details of her proposed referendum, which has been hanging in the air since June 23, 2016 when the UK voted to leave the EU. Most Scots voted to remain.

Since the Brexit vote, the Scottish Government has repeated called for a bespoke arrangement with the European Union. In December, a policy paper entitled "Scotland's Place in Europe" proposed remaining in the single market even as the rest of the UK left. The following month, May said she "could not possibly" entertain such a scenario.

Read: Scotland pitches plan to stay inside EU market

War of words with Westminister

A plebiscite is not, however, in Sturgeon's gift. Her party dominates Scottish politics, and has been in power for a decade in the devolved legislature in Edinburgh. But the Scottish Government cannot hold a second vote without Westminster's acquiescence.

Next week, Sturgeon will formally ask the Scottish parliament - where there is a pro-independence majority - for permission to hold a referendum.

Read: Scotland to seek approval for new independence vote

Scottish nationalists would like a vote after the Article 50 negotiations are completed but before the UK formally leaves the EU. "At the end of that process either the people of Scotland will choose the UK government's Brexit package…or they would choose independence," the Scottish Government's Brexit minister Michael Russell said earlier this week.

"It is the exact opposite of 2014 when the 'yes' camp wanted the campaign to be as long as possible, and unionists wanted it over quickly," says Peter Lynch, senior lecturer in politics at Stirling University and author of a biography of the SNP. "This time around unionists will want to hold off as long as they can."

In 2014 Scots voted by a 10-point margin to reject independence. Sturgeon is hoping that the prospect of leaving the EU - and a 'hard Brexit' outside the single market - will make the nationalist pitch more compelling. But so far polls have yet to register a significant rise in support for going it alone.

Where's the support?

Independence supporters still face a number of questions, particularly on the economy. Oil was a central plank of the SNP's case last time out. But after more than two years of rock bottom prices, the tax take from the North Sea oil and gas industry has collapsed.

Falling oil prices are not the nationalist's only difficulty. The middle-classes - often the strongest 'no' voters last time out - remain unconvinced by independence. Scotland does 64 percent of its business with the rest of the UK.

Yet there could be opportunities for the independence side second time around. During the last campaign, 'yes' was firmly the choice of uncertainty, with question marks over everything from currency to EU membership. Some of these issues remain unresolved, but an independent Scotland is likely to get a far more sympathetic hearing in Brussels now, even allowing for Spanish concerns about secessionist precedents.

The tenor of the next referendum campaign could be very different, too. In 2014, the victorious pro-union Better Together side largely comprised Labour activists. Labour, for so long the dominant party in Scotland, is now in the doldrums. The Scottish Conservatives have emerged as unionist torch-bearers. Their feisty leader Ruth Davidson is popular but the Tory brand is still toxic in much of the post-industrial Scotland.

"How did Tories do so well in 2015? Online targeting of voters. How did leave win in 2016? Online targeting of voters. We could see this here next time," says Lynch.

Not on May's watch?

Andy Maciver, a former Scottish Conservative Head of Communications, believes that May's best strategy would be to reach an accommodation with Sturgeon on a second referendum and make a strong case for keeping the three-centuries-old union between Scotland and England.

Read: In Scotland, independence back on the agenda

May insisted at Friday's Conservative party conference in Cardiff that "now is not the time" for a second Scottish independence vote, adding that the prospect of a Scottish breakaway would threaten the UK's in its negotiations with the EU.

The UK prime minister is likely to insist that any "referendum has to be post-Brexit," says Maciver. "It remains to be seen how that will play, but it'll be the key debate in the early part of the campaign."

A referendum might be avoided altogether, if a deal on Brexit can be hammered out between London and Edinburgh. Angus Robertson, the SNP's leader in Westminster, said the UK government could reach a compromise that protected "Scotland's place in Europe."

But such an arrangement could prove politically difficult given May's commitment to all of the UK exiting the EU on the same terms and the pressures within her Conservative party to take a hard line on Scottish nationalism.

Many independence supporters, too, will accept nothing less than a second referendum. "There is a mandate for a second referendum," says Kevin Gibney. "It will be very tight again, I imagine, but I think we can win."