Charles Kennedy, who led Britain's Liberal Democrats to one of its best election results ever before resigning dramatically after admitting he was receiving treatment for an alcohol problem, has died. He was 55.

Kennedy's family said in a statement Tuesday they were devastated by his death. They did not announce the cause.

Taking over from Paddy Ashdown in 1999, Kennedy helped build the party to its best result in 80 years — winning 62 seats in 2005 — and was a vocal opponent of the invasion of Iraq in 2003.

He resigned in 2006 amid rumors about his drinking. He lost his parliamentary seat in last month's general election.

The party's most recent leader, Nick Clegg, led the tributes to Kennedy, noting that he remained modest about his achievements.