ALEX Salmond has paid tribute to "formidable opponent" Alistair Darling, who was the figurehead of the No campaign, after his death aged 70.
The former first minister, and now Alba party leader, said that despite being in opposite camps during the 2014 referendum campaign, they did not "ever exchange a cross word".
First Minister Humza Yousaf also said he was "deeply saddened" by the news as figures from across the political spectrum paid tribute to the former Labour chancellor.
In a statement, Salmond said: “Alistair Darling was a hugely significant figure in UK politics. I always found him an effective politician.
"He became chancellor at an extremely difficult period but he presented as a calm and authoritative figure during the financial crisis.
"During the referendum campaign he was a formidable opponent on behalf of the Better Together campaign.
"However, outwith the political debates I can say we did not ever exchange a cross word. Alistair was an extremely courteous man.
"Condolences go out to his family. “
Salmond and Darling repeatedly faced each other during televised debates during the 2014 referendum.
Writing on Twitter/X, Yousaf said: "I am deeply saddened to hear of Alistair's passing. He dedicated his life to public service and was a giant of Scottish politics.
"My thoughts with his wife Margaret, children, family, friends and colleagues at this sad time."
Former first minister Nicola Sturgeon added: "Very sad to hear the news of Alistair Darling’s untimely death.
"Though we were on opposing sides of the independence referendum – with the inevitable clashes that involved – I always found him to be a man of intellect and principle. He made a significant contribution to politics."
Former Labour prime minister Gordon Brown said Darling will be remembered as a "statesman of unimpeachable integrity".
“As the chair of the Better Together campaign for the 2014 Scottish referendum he was resolute and courageous in making the case for Scotland’s place in the United Kingdom," Brown said.
"He was held in the highest esteem by me and all who worked with him for the way in which he handled the fall of the major banks and negotiated international agreements with fellow finance ministers.
“I, like many, relied on his wisdom, calmness in a crisis and his humour.
“Alistair’s family were central to everything he did. I send my deepest condolences to his loving wife Maggie and their children Calum and Anna. He will be missed by all who knew and respected him and benefited from the great work he did.”
Scottish Greens co-leader Patrick Harvie said Darling's death was a "significant loss".
“His career was influential not just on Scottish and UK politics, but also on the global stage," he added.
"As Chancellor, he took on a huge responsibility at a time of extraordinary crisis, and he earned respect which went far beyond his colleagues in the Labour Party.
Meanwhile, SNP Westminster leader Stephen Flynn wrote: "The public deserves politicians who act with courage and on the basis of their convictions.
"Alistair displayed those qualities throughout his career in public life and will rightly be remembered by many. My thoughts are with his family, friends and Labour Party colleagues."
Joanna Cherry, SNP MP for Edinburgh South West, the seat Darling held before he stood down in 2015, said: “I am so sorry to read this sad news. Alastair was a good and extremely able man. I was privileged to have him as my constituency predecessor.
“Where he disagreed he always did so respectfully. My heartfelt condolences to his wife and family.”
Chancellor Jeremy Hunt said: “One of the great chancellors, he’ll be remembered for doing the right thing for the country at a time of extraordinary turmoil.
“My deepest sympathies to his family.”
UK Labour leader Keir Starmer said Darling lived a “life devoted to public service”.
He added: “He will be remembered as the Chancellor whose calm expertise and honesty helped to guide Britain through the tumult of the global financial crisis.
“He was a lifelong advocate for Scotland and the Scottish people and his greatest professional pride came from representing his constituents in Edinburgh.”
Former Scottish Labour leader Kezia Dugdale said she was “desperately sad” to hear the news of Darling’s death.
She wrote: “What a giant of man. Compelling intellect, wicked sense of humour, phenomenal public servant and the most loving father and husband. Such a great, great loss.”
Alistair Campbell, the former Labour Downing Street spin doctor, wrote: “So so sad to hear Alistair Darling has died. A lovely man who always put others before himself. A team player.
“He did a succession of Cabinet jobs from start to finish of the New Labour era and did every one of them well. Last time I saw him not that long ago he seemed fit and well.
“Shocking news. A case of the good dying young.”
John Swinney, former Scottish deputy first minister, paid tribute, adding: “Terribly sorry to hear this sad news of the untimely death of Alistair Darling.
“He held office in the incredibly difficult days of the financial crash and acted with skill and care. We always enjoyed friendly and courteous dialogue.
“I am so sorry for Maggie and her family.”
Elsewhere, HM Treasury posted on social media: “Today our thoughts are with the friends, family and former colleagues of Alistair Darling, Chancellor of the Exchequer from 2007 – 2010.”