NICOLA Sturgeon will today insist an independent Scotland offers an oasis of optimism in the face of Brexit chaos as she tries to keep a lid on tensions over a second referendum.

The First Minister will tell the SNP conference in Glasgow it is up to the party to offer hope in the midst of the unfolding calamity engulfing Westminster.

Under pressure from the Yes movement to accelerate the push for independence, she said she might use her mandate to demand a new vote before the 2021 Holyrood election.

She told ITV: “I’d like there to be a second independence referendum yesterday and failing yesterday, tomorrow – but it’s not just down to what I want.”

But critics insisted there was nothing optimistic about breaking up the UK and called on Ms Sturgeon to take a “divisive and unnecessary” second referendum off the table.

Ms Sturgeon’s difficulties in balancing the cautious and gung-ho factions in her party were highlighted by one of her senior MPs suggesting independence could be achieved without a repeat of 2014’s referendum – flying in the face of party policy.

Angus Brendan MacNeil, who has been the MP for the Western Isles since 2005, said the SNP must not “dither” and instead act on independence here and now.

He told conference delegates that “another way” would have to be found if the UK Government refused to allow a legally binding vote through a so-called Section 30 order.

Meanwhile, SNP Brexit Secretary Mike Russell told a fringe meeting that there would have to be discussions about what happened next if unionist parties blocked a fresh referendum.

It comes after Joanna Cherry QC, the SNP’s justice spokeswoman at Westminster, said Scotland could break off from the UK without a second vote.

She insisted a “democratic event” such as a general election would be enough, but critics branded her comments dangerous and ill-judged. The SNP’s official position is that a referendum is necessary. Ms Sturgeon has argued a fresh independence push can only be made once the outcome of the Brexit negotiations becomes clear.

But yesterday she said a second referendum before 2021 was “still possible”, stressing the Scottish Parliament has a mandate to push ahead with a new vote.

Deputy leader Keith Brown told SNP delegates the party was “stepping up the campaign for independence”. But the cautious approach favoured by the leadership provoked unhappiness among some delegates. One told a Brexit fringe meeting that members were “very frustrated with constantly being told to just wait” and suggested time was “slipping away”.

Addressing the SNP conference, Ms Sturgeon will insist an independent Scotland would offer an escape from the chaos engulfing Westminster. She will say: “The Westminster Government stumbles from day to day and disaster to disaster. It’s hard to watch that unfolding calamity and feel anything other than despair.

“So it is up to us – now more than ever – to offer optimism and hope.

“Just think how much more hope will be possible when we take Scotland’s future into Scotland’s hands and become an independent country.

“An independent Scotland, just as Scotland is now, will be a beacon for progressive values – equality, opportunity, diversity and fairness.

“Indeed those values feel more important today than ever before in my lifetime.”

The First Minister will insist the SNP Government is working “day in, day out, step by step, to change lives for the better”.

She will announce a new default position – dubbed “Fair Work First” – which will see firms receiving Government contracts and grants required to pay the living wage, ditch zero-hours contracts and take action on gender pay gaps.

Scottish Tory chief whip Maurice Golden said Ms Sturgeon had “led the SNP troops half way into battle, and then called halt”.

He said: “When it comes to Scotland’s future, everyone in the SNP has an opinion but nobody has a plan.

“All the while, Scotland’s schools are going backwards, waiting times are being missed, and the economy is in the slow lane.

Nicola Sturgeon can show leadership today by doing the right thing: and taking a second referendum off the table. The SNP army might not like it, but at least they’d know what was going on.”

Pamela Nash, chief executive of anti-independence group Scotland in Union, insisted there was “nothing optimistic about Scotland leaving the United Kingdom”.

It comes as a new poll found Scottish voters overwhelmingly back Holyrood having the final say on whether another independence referendum should be held.

A total of 59 per cent said the Scottish Parliament should decide, while just 30% said it should be down to Westminster.