Labour MP for Glenrothes John MacDougall has died following a long battle against asbestos-related cancer mesothelioma.
Mr MacDougall, 60, a close friend and political ally of neighbouring Kirkcaldy and Cowdenbeath MP Gordon Brown, died on Wednesday morning at the Victoria Hospital in Kirkcaldy, Fife.
A Labour Party spokesman said: "All our thoughts are with his family at this time."
Mr Brown visited Mr MacDougall in hospital on Monday and spent time chatting to him. His death will now trigger a by-election.
The last by-election fought in Fife, in February 2006, saw the Liberal Democrats seize power in a strong Labour seat.
Former oil rig construction yard worker Mr MacDougall underwent surgery at Guy's Hospital in London last year in a bid to treat his cancer.
He had served Fife for more than 20 years, after being elected to Fife Regional Council in 1982.
Mr MacDougall later became the leader of the council and also served as the director of Glenrothes Development Corporation and Fife Enterprise before being elected to the House of Commons.
He was elected as the MP for Central Fife in 2001.
Copyright © PA Business 2008
Adrian Budgen from law firm Irwin Mitchell said: This is a tragedy and is deeply upsetting for John MacDougall's family and close friends, as it is for anyone else who has lost a close relative or friend to mesothelioma. Our hearts go out to his family at this very sad time. Mr MacDougall's death will reveal the full extent of the (so called) silent epidemic, as he is the first serving MP to die from the disease. Mesothelioma is now a disease of the person on the street, as it is affecting people from all walks of life."