Former SNP leader Gordon Wilson said Alex Salmond fought a brilliant referendum campaign.

He said: "It is not his fault that the Scottish people did not vote for independence on this occasion. The winning of 45% of the vote in the Scottish independence referendum is a superlative achievement.

"It is a mark of Alex's integrity that he has taken personal responsibility.

"He is undoubtedly the greatest Scottish politician of his generation."

Image source, Joe Murphy

The London Evening Standard - an evening paper - has splashed on David Cameron's pledge for "English votes for English laws" - this picture tweeted by the paper's political editor, Joe Murphy.

Mr Darling added: "He has rightly said that the referendum was a once in a lifetime event and that we all need to work to bring Scotland together.

"He can look back with pride on being the longest serving first minister and to the huge contribution he has made to public life in Scotland.

"I wish him well in the future."

Better Together campaign leader Alistair Darling said: "Alex Salmond is a formidable political figure. He transformed the SNP into a party of government and delivered their referendum on independence which they had craved so long.

"Today he has accepted Scotland's verdict, recognising that it is for others in his party to take the SNP forward."

Mr Salmond reiterates that he has no plans to withdraw or retire from political life, when asked about his future by BBC Newsnight's Kirsty Wark.

Ms Lamont, who faced Mr Salmond on a weekly basis at first minister's questions, said: "I do not detract from his achievements when I say that his love of Scottish independence sometimes blinded him to its consequences.

"He should be proud of his career and not allow the manner of its ending to dominate his thinking.

"There is no question that Nicola Sturgeon and he were a formidable team."

Scottish Labour leader Johann Lamont said: "Alex Salmond turned a minority party into a party of opposition into a party of government and was responsible for there being a referendum on Scotland leaving the United Kingdom.

"He has undoubtedly been an immense figure in Scottish political history."

London editor of news and opinion website The Daily Beast, Nico Hines, tweets, external: Christ, everyone is in tears at Holyrood. Incredible scenes. It's like a funeral

MP for Glasgow Central Anas Sarwar tweets, external: Haven't always agreed with Alex Salmond's politics but recognise his contribution & commitment to Scotland. Wish him well for the future

Business leaders have paid tribute to Alex Salmond, following his resignation.

The Federation of Small Businesses, which has 20,000 members, said he had made "a huge contribution" to Scottish public life and wished him well for the future.

Ruth Davidson argued that Alex Salmond's "decision to step down will help our country come back together again".

She added: "I am pleased that the first minister says he will continue to serve in Scottish politics.

"Scotland will benefit from his experience and service as we move forward."

Scottish Conservative leader Ruth Davidson said: "Alex Salmond has been the dominant figure in Scottish politics for the last seven years.

"No-one can dispute his political achievements, nor fail to acknowledge his political gifts.

"He has done the right thing in resigning.

"While the referendum campaign has been hugely invigorating, by its very nature it has divided too."

Shona Robison, SNP MSP for Dundee, tweets, external: Really sad day, but watching the resignation of @AlexSalmond as FM, he has done so in a great statesmanlike manner

Andrew Black
Political reporter, BBC Scotland

Nicola Sturgeon would be a clear frontrunner to take over as SNP leader and first minister after Mr Salmond steps down, but the question of who would succeed Ms Sturgeon as deputy is much less clear.

Last time round, Mr Salmond and Ms Sturgeon stood for the SNP leadership on a joint ticket.

In a statement, Deputy First Minister Nicola Sturgeon has just said she could think of "no greater privilege" than leading the SNP, adding that the decision to stand was "not for today".

Back in April, Deputy First Minister Nicola Sturgeon spoke to the BBC's Marianne Taylor about her life and career, and the responsibilities of power.

Image source, Kim Karam

"Alex's announcement today inevitably raises the question of whether I will be a candidate to succeed him as SNP leader," she added.

"I can think of no greater privilege than to seek to lead the Party I joined when I was just 16. However, that decision is not for today.

"My priority this weekend, after a long and hard campaign, is to get some rest and spend time with my family. I also want the focus over the next few days to be on the outstanding record and achievements of the finest first minister Scotland has had."

Ms Sturgeon added: "The personal debt of gratitude I owe Alex is immeasurable. He has been my friend, mentor and colleague for more than 20 years. Quite simply, I would not have been able to do what I have in politics without his constant advice, guidance and support through all these years."

Deputy First Minister Nicola Sturgeon said: "Alex Salmond's achievements as SNP leader and Scotland's first minister are second to none.

"He led the SNP into government and has given our country a renewed self confidence. Through policies such as the council tax freeze, free prescriptions and the scrapping of tuition fees, he has made a real difference for hundreds of thousands of Scots. And yesterday he inspired 1.6 million of our fellow citizens to vote Yes to independence."

Alex Salmond may not have achieved the ultimate prize of Scottish independence - and has now stood down as SNP leader and first minister - but no-one should doubt the scale of his achievements, says BBC political reporter Brian Wheeler.

John Curtice, polling expert and professor of politics at Strathclyde University, says Mr Salmond "has form in providing us with shocks when it comes to the leadership of the SNP".

"Some must remember the summer of 2000 when suddenly he announced he was standing down as leader of the SNP and was leaving the Scottish Parliament... then in the summer of 2004, he suddenly announced that in fact he was going to stand as leader again.

"He spots opportunities and as a result of that he does provide us with shocks."