Johann Lamont is to stand down as the leader of the Scottish Labour Party.
The Glasgow Pollok MSP has represented her constituency since 1999 and has been leader since December 2011.
In the weeks after the referendum Ms Lamont said she wanted to lead Labour in to the 2016 Holyrood elections and become First Minister but despite being part of the victorious campaign for a No vote she has decided to resign.
In an interview with the Daily Record Ms Lamont said she was proud of what the party had achieved.
"I am standing down so that the debate our country demands can take place," she told the newspaper.
"I firmly believe that Scotland's place is in the UK and I do not believe in powers for power's sake.
"For example, I think power should be devolved from Holyrood to communities. But colleagues need to realise that the focus of Scottish politics is now Holyrood, not Westminster."
“There is a danger of Scottish politics being between two sets of dinosaurs … the Nationalists who can’t accept they were rejected by the people, and some colleagues at Westminster who think nothing has changed.”
MP Anas Sarwar was elected deputy of the Scottish Labour Party at the same time as Ms Lamont became leader.
A UK Labour party source said: "She realised it was time for a change in Scotland, she has put the party first.
"Ed (Miliband) regards her as an honourable woman who has served the party well and we hope will serve the party again in the future."
Ms Lamont is the second Scottish party leader to resign following the referendum after First Minister Alex Salmond decided to step down from his role.
Mr Salmond will be replaced as First Minister and SNP party leader by deputy Nicola Sturgeon at their party conference in Perth next month.
Ms Lamont joined the Labour Party as a teenager, and spent 20 years as an English teacher before being elected to represent Pollok at Holyrood.
She took over as the party's Scottish leader in the aftermath of the 2011 election, where Labour suffered one its worst defeats in Scotland.
Earlier this week, Scottish Labour was described as "going through a period of reflection" after last month's independence referendum, which saw large numbers of the party's supporters vote to leave the UK, despite the overall majority of Scots backing the union.
Senior party figures said it needed to rediscover its "sense of purpose".
Former Labour first minister Lord McConnell said that the party had become "a political machine that is angry about what has happened in Scotland in the recent past" and must now rediscover its "sense of purpose".
Shadow Scottish Secretary Margaret Curran argued that the party was already changing but said it needs to return to its "socialist principles".
Nicola Sturgeon, who is to become First Minister next month, tweeted that she wished Ms Lamont well but added that if reports of divisions between the Scottish and UK Labour parties were accurate then "scottishlabour really is in meltdown".
Green MSP Patrick Harvie, who is part of the Smith Commission discussing further devolution for Scotland, said: "I'd like to wish her well and express hope that those seeking change within the Scottish Labour Party can make progress - Scottish voters deserve to have the option of an effective Labour Party which can advocate the values and principles which its UK leadership has sadly long ago surrendered."Reuse content