Scottish First Minister Nicola Sturgeon to stand down with no clear successor

Nicola Sturgeon, who has dominated Scottish politics for almost a decade as first minister, is expected to quit on Wednesday, standing down with no obvious successor in place and dealing a blow to the fight for independence.

Sturgeon, 52, became the leader of the ruling Scottish National Party (SNP) in the wake of its 2014 independence referendum when the country voted 55% to 45% to remain as part of the United Kingdom.

She led her party to a resounding success at the 2015 UK election, winning 56 of 59 seats in Scotland and establishing it as Britain's third largest party, before she retained control over the devolved parliament at more recent elections.

Why is Sturgeon resigning?

But she has recently become embroiled in a row with the London government of Prime Minister Rishi Sunak, and some of her own voters, over a gender recognition bill and London has blocked the path to another independence referendum.

"She's had enough," the BBC cited a source close to Sturgeon as saying.

Sturgeon's SNP suffered a blow in November when the United Kingdom's top court ruled that her Scottish government could not hold a second referendum without approval from the British parliament.

Successive Conservative governments in London have said the 2014 referendum was a once-in-a-generation decision and could not be repeated so soon.

Sturgeon said in response that she would turn the next British general election into a de facto referendum to ramp up pressure on London to grant another vote.

"There's almost a vacuum that comes after her, because there's nobody now who is a clear and obvious successor to take over," Anthony Wells, Head of European Political and Social Research at YouGov UK, told Reuters.

He said Sturgeon's strength at the top of the party had contained internal disputes over the way forward: "Without somebody clearly with her hand on the tiller, I guess it will be a bit chaotic."

According to polls, support for independence rose above 50% in the wake of the Supreme Court defeat but has since slipped back.

In recent months, Sturgeon became embroiled in a row over transgender policies after Scotland passed a bill to make it easier for people to change their legal gender.

Sunak's government said it would block the bill because it could impact the law in the rest of the United Kingdom.

But the row turned the spotlight on the treatment of transgender people in Scottish prisons, with Sturgeon facing difficult questions after a transgender woman convicted of rape was initially placed in an all-female prison.

Scotland has since said it would review the management of trans prisoners.

The Scottish government declined to comment on the reports of Sturgeon's resignation.