Nicola Sturgeon has been first minister since November 2014. Photo: AFP
By Glenn Campbell
Nicola Sturgeon is to resign as Scotland's first minister after more than eight years in the role.
The Scottish National Party leader was expected to make the announcement at a hastily-arranged news conference in Edinburgh.
It was not thought that her departure will be immediate, allowing time for a successor to be elected.
A source close to Sturgeon - the longest-serving first minister - told the BBC that she had "had enough".
Sturgeon has been first minister since November 2014, when she took over from Alex Salmond following the independence referendum.
The first minister was due to hold a press conference at Bute House in Edinburgh at 11am local time.
Sturgeon has been a member of the Scottish Parliament since 1999, and became the deputy leader of the SNP in 2004.
She then took over from Salmond as leader and first minister after the defeat in the 2014 referendum.
Sturgeon has led the SNP to a series of election victories at UK, Scottish and local level.
Last year the UK Supreme Court ruled that Holyrood did not have the power to stage another independence referendum - a move which has been blocked by the UK government
Sturgeon had said she wanted the SNP to fight the next general election as a de facto referendum, but there has been some opposition to the plan within the SNP.
In addition, recent months have seen controversies over gender reforms, which have been blocked by the UK government.
Alison Thewliss, the SNP MP for Glasgow Central, said she was "absolutely gutted" at the news of Sturgeon resignation.
She tweeted: "Nicola has been an incredible leader."
- BBC