SUPPORT for Scottish independence has leapt after Theresa May’s “hard Brexit” speech which confirmed that the UK would leave the single market.

An exclusive BMG survey for The Herald reveals that 49 per cent of Scots support independence with 51 per cent backing the Union, when “don’t knows” are removed.

But most Scots oppose holding a second independence referendum before the UK leaves the European Union.

Read more: Labour rebels side with Tories as Holyrood votes against Article 50

The poll findings emerged as the Prime Minister saw off an attempt by opponents to secure an effective veto over her Brexit deal.

By a majority of 33, MPs voted against a Labour amendment that would have stopped ministers striking a Brexit agreement until it had been passed by MPs and peers. Seven Conservative MPs voted with Labour.

Mrs May has promised MPs a “take it or leave it” vote on the final draft of any EU exit agreement, a commitment initially hailed by Labour as a “huge” concession.

But it means that if MPs reject the final deal, Britain will leave the EU with no terms of exit.

At Holyrood, MSPs voted overwhelmingly by almost two-to-one against triggering the formal process to leave the EU in a symbolic ballot yesterday.

The SNP, Greens, Liberal Democrats and most Labour MSPs supported the motion, with three Labour MSPs – Neil Findlay, Elaine Smith and Richard Leonard – defying the party whip and opposing it alongside the Conservatives.

Today’s poll points to the gap between support for independence and Unionism narrowing markedly in what will be seen as a boost for Nicola Sturgeon’s government.

A similar survey published last month found 45.5 per cent in favour of independence with 54.5 per cent against – roughly the same result as the 2014 referendum.

These latest figures represent a high-water mark for independence following an initial surge in support following June’s Brexit vote.

Read more: Labour rebels side with Tories as Holyrood votes against Article 50

Dr Michael Turner, research director at BMG, said that the poll – the first since the Prime Minister confirmed that she was opting for a “hard Brexit” last month – painted a mixed picture, “with Brexit undoubtedly having an effect on support for the principle of independence”.

He added: “However, although the results do show a clear rise in support since May’s speech, which suggested that the UK may go for a harder form of Brexit than first thought, they also suggest a majority of Scots may not have the appetite for another referendum before the Brexit negotiations are concluded.

“Although these results suggest that opposition to independence is by no means an insurmountable task for Nicola Sturgeon’s SNP, they do imply that she is a fair way off from her ‘red-lines’ of clear and consistent support.”

In the immediate aftermath of the EU referendum, several polls suggested a majority of Scots wanted to break away from the rest of the UK but later surveys showed that sentiment began to ebb away.

Mrs May announced that the UK would leave the single market but attempt to maintain the “greatest possible access” to it.

She also warned that the UK reserved the right to walk away from talks with Brussels, insisting that that no deal was “better than a bad deal”.

Nicola Sturgeon said the Prime Minister’s Brexit strategy had made a second referendum on independence “more likely”.

Despite the polls narrowing on the constitutional question, the BMG research also found that most Scots oppose the prospect of another independence referendum before the UK leaves the EU.

Opposition to another vote before then outweighs support by 56 per cent to 44 per cent, when “don’t knows” are excluded, the poll suggests.

Nicola Sturgeon has ruled out holding a referendum this year, but she has repeatedly said that another independence vote remains “on the table”.

Read more: Labour rebels side with Tories as Holyrood votes against Article 50

Last night, the SNP said the poll indicated that the more the Conservative government pursues a “hard Brexit” the more voters in Scotland will view independence as the best option.

But pro-Union parties said that the results again showed that Ms Sturgeon was falling short of her aim of majority support for independence.

Finance secretary Derek Mackay, SNP MSP for Renfrewshire North and West, said: “The Tories now think they can do whatever they want to Scotland and get away with it – but this poll suggests their arrogance and complacency is badly misplaced.”

He added: “If the Tories continue with their blind pursuit of a hard Brexit, ignoring the clear view of an overwhelming majority of people in Scotland, then more and more people will see independence as the option delivering certainty and stability.”

Scottish Conservative constitution spokesman Adam Tomkins said that the BMG survey was the latest to show there is insufficient support for independence or a re-run of the 2014 referendum.

He said: “By her own measure, this should be enough for Nicola Sturgeon to call off her threat of another separation vote.

“The findings from this poll are clear – the SNP should focus on getting a good Brexit deal for Scotland and the UK, not use the process for independence rabble-rousing.” A Scottish Labour spokesman called on Ms Sturgeon to rule out another independence referendum.

He said: “People in Scotland are very clear that they don’t want another independence referendum.” Lib Dem MSP Alex Cole-Hamilton said that the shift of support on independence was not “meaningful”.

He added: “The poll also shows a great reluctance among Scottish people to thrash this out again.” BMG Research interviewed 1,067 adults living in Scotland between January 26 and 31.