LONDON (AFP) - Scotland's pro-independence leader on Wednesday (Nov 14) voiced her opposition to a draft Brexit agreement that would reportedly leave Northern Ireland in the European single market.

First Minister Nicola Sturgeon, who wants Scotland to be allowed to remain in the single market and the customs union, said that the deal would give Northern Ireland an unfair advantage.

Mainland Britain, including Scotland, would still have to leave the single market, according to British media reports.

"That would be devastating for investment and jobs in Scotland," Sturgeon, who heads the ruling Scottish National Party (SNP), said in a video posted on her Twitter page.

She said it would be "the worst of all possible worlds".

But she added that the deal could still be voted down by the British parliament which could open the way for "better options" including single market membership for Britain as a whole.

Ross Thomson, a Scottish MP from Prime Minister Theresa May's Conservative Party, which is in opposition to the SNP in Scotland, on Wednesday also said that the deal was "unacceptable".

"I fought head, heart, body and soul to save our Union in 2014," he said referring to a Scottish referendum on independence.

"If the news reports are true the backstop would result in Northern Ireland diverging unconsciously from the UK and it would fundamentally undermine our Union, breaking it up by the back door."

Scotland voted overwhelmingly to remain in the European Union by 63 per cent in the 2016 referendum, but the overall national vote was 52 per cent in favour of leaving the bloc.

That vote came two years after Scotland held its vote on independence in which 55 per cent opted to remain part of Britain.

Sturgeon has argued that the Brexit vote changes the context but is holding off on calling for a second independence referendum.