David Dunwoody said his hospitalized mother died "in a gentle and calm way" after about a week's illness, The Times of London reported.

Dunwoody's death deprives the Labor Party of one of its stalwarts and hands Prime Minister Gordon Brown an inconvenient by-election. Her Crewe and Nantwich constituency was considered a safe Labor seat and a loss at a time when Brown and his party are unpopular would be an embarrassment.

Born Gwyneth Phillips, Dunwoody was the daughter of Morgan Phillips, general secretary of the Labor Party.

In the House, she was known as an advocate of public transportation -- she headed the Transport Select Committee -- and of rights for back-benchers. In 1998, she campaigned to have the original Winnie the Pooh toys returned from New York to London, getting into a public spat with New York Mayor Rudy Giuliani that made international headlines.