NICOLA Sturgeon has been challenged to set out the terms of the UK Brexit deal that would persuade her to abandon plans for a second independence referendum.

The First Minister this week revealed that draft legislation that would lead to a second referendum would be published and consulted upon, allowing her to pull the trigger on a repeat independence vote if the SNP leader concludes it is "the best or only way to protect Scotland's interests."

After making a statement to Holyrood yesterday on her work to protect Scotland's place in the EU, Ms Sturgeon faced calls to spell out under what circumstances the life-long nationalist would decide remaining in the UK is the best option when she comes to make her decision over a referendum.

Ruth Davidson, the Scottish Tory leader, said: "The First Minister declares that independence will be considered 'only if it is best or only way to protect our membership in the EU'.

"But can the First Minister honestly tell the chamber, under what circumstances and on what issue she has ever concluded that it isn't the best option for Scotland?

"More fundamentally, Nicola Sturgeon says leaving this trading bloc is bad for Scotland. So why does she believe that leaving one that is four times as important in terms of trade is the answer to any of these questions?"

The First Minister has set out an ambitious wishlist of five key demands she would like to see in any post-Brexit deal, which include membership of the single market and maintaining influence over how EU rules are made. She also said this week that leaving the EU against the wishes of Scottish voters is "not in Scotland’s national interest" while also acknowledging that the UK would "surely" be leaving in light of the EU referendum result.

Willie Rennie said that Ms Sturgeon was correct to challenge the UK Government over a lack of clarity over the terms of a Brexit deal, amid growing confusion over Theresa May's stance on key issues such as whether the UK will stay in the single market. However, the Scottish Liberal Democrat leader said Ms Sturgeon had "some questions to answer herself."

He added: "Everyone knows the SNP want independence but the First Minister is expecting us to believe that there are possibly circumstances where she could conclude that a second referendum is not the answer. She needs to set out what those circumstances would be, or end the charade and admit that a second independence poll is her only priority for Brexit."

The First Minister has repeatedly stated that she will consider all options, including another independence vote which she says she is "highly likely" to call, to protect Scotland's EU membership.

She added: "To give up the right to even consider that option [independence] would be to accept we are at the mercy of Westminster decisions no matter how damaging or destructive they are to our society, our economy or place in the world."

Responding to Ms Davidson, the First Minister argued that UK ministers had assured Northern Ireland that trade links with the south would be maintained post-Brexit, meaning the same could apply to an independent Scotland post-Brexit.

She added: "I will always seek to behave in the best interests of the people of Scotland, that's why I will not rule out options that may be required to protect Scotland's interest. But I think Ruth Davidson should be reflecting very hard on this - two years ago she said to the people of Scotland that the only way to guarantee membership of the EU was to vote against independence.

"Now her party is taking us to the brink of exit, she is still trying to say independence in no circumstances is the answer to that. It is Ruth Davidson that is inconsistent."