Nicola Sturgeon: real risk UK will suffer a lost decade or more after leaving European Union

She stated: "The damage that will then do to our economy and other areas of our society and life will be deep and severe."

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Ms Sturgeon voiced her concerns as she told a Holyrood committee that in her view there is a "pretty compelling" case for the UK Parliament to have a vote on the triggering of Article 50, which will formally start the withdrawal process.

If that happened, she said Holyrood could also have to give its backing for this, with MSPs potentially voting on a legislative consent motion (LCM)

With the leaders of all five parties in the Scottish Parliament having campaigned to remain in Europe, this opens up the prospect of Holyrood blocking the use of Article 50.

Ms Sturgeon said the Scottish Government is monitoring the legal cases that have been brought in a bid to determine if Theresa May and the UK Government can do this without the formal consent of Parliament.

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It comes as talks are taking place between Holyrood and Westminster over the role the devolved administration should have in Brexit negotiations.

While Mike Russell, the recently-appointed minister for UK negotiations on Scotland's place in Europe, is to meet Brexit Secretary David Davis in London on Thursday, Ms Sturgeon conceded the discussions were "not proceeding as quickly as I would like them to".

The First Minister went on to tell MSPs on the European and External Relations Committee the Scottish Government "is keeping a very close eye" on court actions that have been brought in England and Northern Ireland.

The "heart of these actions" centres around whether the UK Government can trigger Article 50 itself or would require an act of parliament to do so.

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The cases are "expected" to go to the UK Supreme Court, she said, and added: "I have no inside knowledge on this but we might well get to a stage where we have a court decision that says Parliament has to be involved in that way.

"I have to say the Scottish Government is keeping a very close eye on these court actions and will assess as they proceed at all stages whether there is an argument for us to become directly involved to make sure that the interests of the Scottish Government and the Scottish Parliament are protected.

"If that was to be the case that there was a decision - and I'm speculating now - that Parliament had to pass legislation, that brings the issue of an LCM into sharp focus.

While there would be a two-year period after Article 50 was triggered for negotiations to take place, Ms Sturgeon said it would take "goodness knows how many years after that" to determine the new relationship between Britain and Europe.

She said: "Presumably there will require to be a transition period, and then how long is a piece of string when it comes to considering the length of time it will take to put in place new trade deals between the UK and not just the EU but other countries.

"I do think there is a real risk that the UK is facing right now a lost decade or more, when the uncertainty and turmoil of Brexit and everything that comes after that, before there is clarity about what the UK's place in Europe and the world actually is will dominate."

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Ms Sturgeon told MSPs in her view the "least worst option" for the UK would be if it could retain its membership of the European single market - which guarantees the free movement of goods and people.

European Commission president Jean-Claude Juncker has already said the UK could not stay in the single market and regain full control over immigration, saying there could not be "a la carte'' access to the free trade zone once Brexit is delivered.

The First Minister and SNP leader also restated her view that if Scotland's interests could no longer be protected by a UK that is outside of the EU, it would be right to have a second referendum on independence.

Within hours of the referendum result, which saw 62% of Scots voters back remain, Ms Sturgeon warned another ballot on the future of the UK was "highly likely".

She told MSPs "if we get to the point whereby we can not protect our interests in the UK, because the UK is heading for a hard Brexit" that would damage exports, the financial services industry, universities and others.

"If we end up in that kind of position then I think it would be wrong to deny people in Scotland the right to consider whether independence is a better way of protecting those interests," she said.

She stressed another independence referendum is "not the starting point" for the Scottish Government, pledging to "methodically and systematically work through all of the options".

During a later debate on the implications of Brexit, opposition politicians questioned Ms Sturgeon's objectives as she seeks to play a key role in any EU negotiations.

Scottish Conservative deputy leader Jackson Carlaw said politicians, including the First Minister, must accept the UK's vote to leave while the public was "weary" of the prospect of another independence referendum.

He said the Scottish Government can "both make or break our influence and an opportunity in the exit negotiating strategy and discussions".

"The First Minister's tone has not been encouraging," he added.

"Her obsession with independence reluctantly persuades us ... that her view of Scotland's interests can only be viewed through that prism."

Labour's Lewis Macdonald questioned whether maintaining UK membership of the single market would fulfil Scottish ministers' mission to protect Scotland's relationship with Europe.

"Does the independence option then come off the table if the UK successfully negotiates continuing membership of the single market?" he asked.

"Mrs May will then have to decide what matters more - keeping ministers in her cabinet who want to leave the single market or getting an independence referendum off the table.

"If, on the other hand, SNP ministers would wish to press on regardless in pursuit of a separate Scottish outcome, then they need to tell us what else is a key objective for them in these negotiations?

"Is membership of the single market a red line for the Scottish Government or is achieving that objective not enough?"

Mr Russell told the chamber the Government's approach to the negotiations was "detailed and comprehensive".

"We stand ready to listen and to speak,"

"To listen to the communities, interests groups and citizens of this country, and understand their many concerns.

"To listen not just to those who voted to remain but also to those who voted to leave and to address their hopes and fears as well.

"As we do so we will build our negotiating stance, informed by those conversations, so that it is focused firmly and relentlessly on how we get the very best deal for Scotland as well as help to get the very best deal for the UK."

Former first minister Alex Salmond was asked about Ms Sturgeon's comments on his weekly LBC radio show.

He said: "I hope and believe and I've got every confidence that Nicola Sturgeon will leave no stone unturned in pursuing the wishes of the Scottish people.

"If Scotland could block Brexit then I think Nicola Sturgeon should do that, of course she should."

A UK Government spokeswoman said afterwards: "As the Prime Minister has said, it would not be right to provide a running commentary or reveal our hand prematurely.

"The Department for Exiting the European Union is leading the UK's negotiations to leave the European Union and establish the future relationship between the EU and the UK.

"The Government has committed to working very closely with Parliament, devolved administrations and a wide range of other interested parties on this approach."