Media playback is unsupported on your device Media caption David Cameron led tributes to the former Liberal Democrat leader

Charles Kennedy was the "most human of politicians", David Cameron has said as he led tributes to the former Liberal Democrat leader in Parliament.

After news of his death on Monday, MPs have been reflecting on Mr Kennedy's contribution to politics and public life in a special Commons session.

The PM said he was "an extraordinary talent" and "a man of great principle".

Mr Kennedy's ex-wife Sarah and his 10-year-old son Donald watched proceedings from one of the public galleries.

Mr Kennedy led the Liberal Democrats for six years and took the party to its best election result in 2005 before being ousted eight months later after revealing he had been receiving treatment for a long-standing drink problem.

* Politics Live - including the tributes as they happened

Mr Kennedy, who lost his Ross, Skye and Lochaber seat in last month's general election, died at his home in Fort William on Monday aged 55. His cause of death has yet to be confirmed.

Media playback is unsupported on your device Media caption A look back at Charles Kennedy's life in politics

Speaking in the Commons, Prime Minister David Cameron said Mr Kennedy was a man of "strong views and great loyalty".

"Charles Kennedy played a pivotal role in bringing together two parties - the SDP and the Liberals. As leader he took the Liberal Democrats to the best electoral result for a third party in British politics for nearly 100 years.

"He told Sue Lawley on Desert Island Discs back in 2003 that his ambition for his party was to find themselves part of a government of the country.

"His achievements laid the foundations for that to happen and, while he was never the greatest fan of the coalition, and indeed voted against its formation, he never spoke out against the Lib Dem participation in it."

Charles Kennedy: 1959-2015

Image copyright Various

By Nick Robinson, BBC political editor

Charles Kennedy left a mark on British politics. The man who took his party to its electoral peak, he was the only UK party leader to warn the country of the perils of invading Iraq when Labour and the Conservatives were uniting to support it.

He was also the only Liberal Democrat MP who could not bring himself to vote to form a coalition with the Conservatives.

But British politics also left its mark on him. Elected at the age of just 23, politics and the House of Commons became his life whilst alcohol was his friend, his prop and his curse.

Read Nick's thoughts

John Pienaar's memories

The Charles Kennedy story

Charles Kennedy's life in pictures

Charles Kennedy in his own words

Scottish tributes

Outgoing Lib Dem leader Nick Clegg said Mr Kennedy would have "wanted to be remembered as a kind and loving father, brother and son first; and an accomplished politician second".

"His good humour must not obscure the fact that there was a steely courage about him, most memorably on display when he took the principled decision to oppose the Iraq War," he said.

"Charles was often a lone voice in this House, standing up against a consensus in favour of war on all sides. The fact that he was proved so spectacularly right is a tribute to his judgment and his intuitive common sense."

'A persuader'

The two men hoping to succeed Mr Clegg as Lib Dem leader said the party would always be indebted to Mr Kennedy.

Norman Lamb said the party must do everything it could "to ensure Charles's legacy, to rebuild the Liberal voice in this country" while Tim Farron said Mr Kennedy "was a persuader and he was a persuader because he was able to reach people in their gut".

Image copyright PA Image caption Nick Clegg: Charles Kennedy was the "polar opposite of a point-scoring party politician".

Acting Labour leader Harriet Harman said Mr Kennedy had been right to oppose the Iraq war in 2003 while the SNP's Angus Robertson said Mr Kennedy "was a giant in Scottish and in UK politics".

Opening the session, Speaker John Bercow said Mr Kennedy had an unique ability to reach out to people normally mistrustful of politicians, describing him as "the boy next door of British public life".

The Lib Dems have opened an online "book of condolence" where anyone can leave messages via its website.

Mr Kennedy's political career began in the Social Democratic Party and he became the youngest MP of the time when he won the Ross, Cromarty and Skye seat in 1983 at the age of 23.

He held a series of frontbench posts when most of his party merged with the Liberals to form the Lib Dems in 1988 and took over the Liberal Democrat leadership from Paddy - now Lord - Ashdown in 1999.

He married former Camelot public relations executive Sarah Gurling in 2002 and their son Donald was born during the 2005 general election campaign. He and his wife split up in 2010.