Sir Menzies Campbell's appearance at this year's Lib Dem conference was his last as party leader. His resignation letter said "questions about leadership" were impeding progress.

In his final months as leader, Sir Menzies Campbell was increasingly under pressure. At times, even simple photo opportunities undermined attempts to appear statesmanlike.

He became Liberal Democrat leader in 2006, after defeating opponents Chris Huhne and Simon Hughes. The victory fulfilled an ambition that spanned his political career.

Despite running a successful leadership campaign, after the resignation of Charles Kennedy, some still saw Sir Menzies as a caretaker rather than long-term leader of the party.

Sir Menzies earned a reputation as an authoritative figure, particularly regarding foreign policy.

Sir Menzies Campbell was awarded a knighthood in 2004. Last month, during the party conference, his wife - Lady Elspeth - defended her husband's leadership against possible rivals.

Sir Menzies Campbell was an Olympic athlete before pursuing a career in law and, later, politics.