Former Liberal Democrat leader Charles Kennedy has died aged 55, his family has said.
Mr Kennedy passed away suddenly at his home in Fort William.
Police Scotland said the death is not being treated as suspicious. A post-mortem is set to be carried out.
A statement released on behalf of his family said: “It is with great sadness, and an enormous sense of shock, that we announce the death of Charles Kennedy.
“Charles died at home in Fort William yesterday. He was 55. We are obviously devastated at the loss.
“Charles was a fine man, a talented politician, and a loving father to his young son. We ask therefore that the privacy of his family is respected in the coming days.
“There will be a post-mortem and we will issue a further statement when funeral arrangements are made.”
Mr Kennedy led the Liberal Democrats from 1999 until 2006.
He was a Member of Parliament from 1983 to 2015 having lost his seat of Ross, Skye, and Lochaber to a challenger from the Scottish National Party last month.
Mr Kennedy led the Liberal Democrats to their best general election result before or since, in 2005, when they gained 62 seats.
Much of his party's popularity at the time was gained by Mr Kennedy's decision to oppose the war in Iraq.
He stepped down as leader after considerable speculation about a drinking problem, which he announced he was getting treatment for at the time.
Charles Kennedy - his political career in pictures
Charles Kennedy - his political career in pictures
Charles Kennedy at the SDP conference in September 1986. He had become Britain's youngest MP three years earlier and the party later merged to become the Liberal Democrats.
Charles Kennedy attends the Joint Liberal Assembly, October 1987.
Getty Images/Hulton Archive
Charles Kennedy being congratulated by his girlfriend and future wife, Sarah Gurling, and mother Mary after being elected Lib Dem leader in 1999
Charles Kennedy greeting supporters at a rally before the 2001 general election, when he was the Lib Dem leader
Mr Kennedy at his wedding to Sarah Gurling, outside the House of Commons in London. The couple divorced in 2010.
Charles Kennedy speaks during a question and answer session at the Liberal Democrat Party annual conference in Brighton
Charles Kennedy and his then wife arrive at the British Academy Television Awards in London
Charles Kennedy unveiling a Lib Dem campaign poster ahead of the 2005 general election
Charles Kennedy with his then wife Sarah and new born son Donald James on 12 April 2005. He returned to the election campaign trail days later
Charles Kennedy celebrating the Lib Dems' gains after the 2005 general election, when the party won 62 seats
Charles Kennedy admitted his drink problem and called a leadership election in January 2006
Charles Kennedy is canvassing in Dunfermline for a by-election a month after his resignation as Lib Dem leader
Sir Menzies Campbell, Lord Rennard and Simon Hughes give Charles Kennedy a standing ovation after his speech to the party conference in September 2006, his first since his resignation
Charles Kennedy and his predecessor Paddy Ashdown congratulating Nick Clegg on his election as Lib Dem leader in December 2007
Charles Kennedy with Nick Clegg on the campaign trail ahead of the 2010 general election
Charles Kennedy launching the pro-AV campaign for the 2011 proportional representation referendum in Glasgow
Charles Kennedy with Danny Alexander and fellow Lib Dems campaigning for a 'no' vote in the Scottish independence referendum in 2014
Charles Kennedy campaigning with Jo Swinson in East Dunbartonshire in April ahead of the 2015 general election, where he lost his seat
He was the only Liberal Democrat MP to vote against the formation of the coalition in 2010.
Tributes poured in for Mr Kennedy from senior figures from across the political spectrum.
In a statement outgoing party leader Nick Clegg said: “Charles's untimely death robs Britain of one of the most gifted politicians of his generation.
“Charles devoted his life to public service, yet he had an unusual gift for speaking about politics with humour and humility which touched people well beyond the world of politics,” he said.
“He was a staunch internationalist and passionate believer in Britain's role in Europe, yet he was a proud Highlander, Scot and British parliamentarian.
“He was one of the most gentle and unflappable politicians I have ever known, yet he was immensely courageous too not least when he spoke for the country against the invasion of Iraq.
“He led the Liberal Democrats to our party's greatest electoral successes, yet he always remained modest about his huge achievements.
“Whenever I asked him for advice, he was unfailingly kind and wise,” the former deputy prime minister added.
“Most of all, I will never forget the pride and love with which he would talk about his own family, most especially his devotion to his son Donald.
“My heart goes out to his sister and brother and to Sarah and Donald at this tragic time.”
On Twitter the former Deputy Prime Minister posted:
Charles Kennedy was one of the most gifted politicians of a generation, he always spoke with great humour, humility and courage.— Nick Clegg (@nick_clegg) June 2, 2015
Paddy Ashdown, Mr Kennedy's predecessor as leader of the Liberal Democrats, tweeted:
Charles Kennedy. In a political age not overburdened with gaiety and good sense, he brought us wit, charm, judgement, principle and decency— Paddy Ashdown (@paddyashdown) June 2, 2015
Scottish First Minister Nicola Sturgeon said:
Sad beyond words to hear the news about Charlie Kennedy. A lovely man and one of the most talented politicians of his time. Gone too soon.— Nicola Sturgeon (@NicolaSturgeon) June 2, 2015
Leadership candidate Tim Farron tweeted:
I am utterly heartbroken about the news of Charles' passing. He was a colleague, friend and mentor. We've lost a giant today.— Tim Farron (@timfarron) June 2, 2015
Another, Norman Lamb, said:
The untimely death of Charles Kennedy - such a tragic loss of a lovely, talented man. My thoughts r with his young son, his family & friends— Norman Lamb (@normanlamb) June 2, 2015
Acting Labour leader Harriet Harman tweeted:
Deeply progressive, a delightful person, with a great intellect. Hugely likeable, Charles Kenedy such a loss.— Harriet Harman (@HarrietHarman) June 2, 2015
Warm tributes also flooded in from members of the public:
I once got lost at night in London Zoo with Charles Kennedy, leaving a recep'n. I can still see him laughing by the aardvarks. RIP @LibDems— Mark Oakley (@CanonOakley) June 2, 2015
Charles Kennedy deserved a longer life than this. When he was leader voting Lib Dem was an obvious choice. Never did so again after he left.— Alex Ingram (@nuttyxander) June 2, 2015
I once found myself doing the washing up and making tea next to Charles Kennedy. Which just about sums him up. Terribly sad news.— Charlotte Henry (@charlotteahenry) June 2, 2015