NICOLA Sturgeon will today set out five key Brexit tests that could determine whether Scotland faces a second independence referendum within the next two years.

The First Minister will use a major speech in Edinburgh to list the "Scottish interests" she believes must be preserved as the UK withdraws from the Brussels bloc.

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They include the need to ensure "Scotland's voice is heard and our wishes respected" - a reference to the referendum on June 23 when a majority of Scots voted to remain part of the EU.

With the UK Government having already having poured cold water on the idea of a Brexit deal that would allow Scotland to remain in the EU, Ms Sturgeon's words will be seen as bringing a re-run of the 2014 vote a step closer.

The First Minister has previously said "remain means remains" and insists independence must be an option for preserving Scotland's relationship with the EU.

She believes a second referendum is "highly likely" following Brexit, provided support for independence remains high.

Her key tests will be set out in a speech to the Institute for Public Policy Research (IPPR) think tank.

It comes after Russell Gunson, the head of IPPR Scotland, said Unionists should take the lead in finding options to maintain the Scotland's relationship with the EU, as a solution could require reform of the whole of the UK.

In other developments yesterday, oil tycoon Sir Ian Wood urged Ms Sturgeon not to call a second independence referendum and Alan Cumming, the actor and Yes campaigner, caused an outcry when he blamed Brexit on "stupid English people".

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In her speech - titled Scotland's future in the EU - Ms Sturgeon will reflect on the campaign and the reasons behind the result.

She will also discuss the forthcoming Brexit negotiations, in which the Scottish Government had been promised a role.

The First Minister is expected to say: "I am determined that we find or create the options that best preserve the five key interests that depend on our relationship with the EU.

"Our democratic interests - the need to make sure Scotland’s voice is heard and our wishes respected.

"Our economic interests - safeguarding free movement of labour, access to a single market of 500 million people and the funding that our farmers and universities depend on.

"Our interests in social protection - ensuring the continued protection of workers’ and wider human rights.

"Our interest in solidarity - the ability of independent nations to come together for the common good of all our citizens, to tackle crime and terrorism and deal with global challenges like climate change.

"And our interest in having influence - making sure that we don't just have to abide by the rules of the single market but also have a say in shaping them."

Ms Sturgeon will promise to "explore every avenue and every option" for meeting the five tests.

But Murdo Fraser, the Scots Tories' finance spokesman, urged her to rule out independence.

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"It is right that the Scottish Government should be examining how best to further our interests as the UK begins negotiations with the EU.

"However, as two million Scots agreed in 2014, leaving the UK is not in Scotland's interests, and the Scottish Government should therefore end its flirtation with yet another divisive referendum on independence," he said.

In a Sunday newspaper article, Mr Gunson wrote: "It is those across the UK who do not wish to see Scottish independence, or those open to exploring all the options, who will need to come forward with other options."

The options "need to be explored with equal vigour and rigour by both the UK and Scottish governments", he said.

"The latter is certainly giving the impression of being up for exploring all the options, but without a genuine commitment in the rest of the UK, and without significant reform to Britain as a whole, a tailored approach to Brexit will not be deliverable.

"And with that, Scotland's options would be narrowed significantly."