Gwyneth Dunwoody, the Labour Party's longest serving woman MP, has died, her son said on Friday.

David Dunwoody said his mother died on Thursday evening after being admitted to hospital last week with an undisclosed illness. She was 77.

"She was a woman who stood up and said what she believed was true and defended those who don't have many people to defend them," Dunwoody told the BBC.

Dunwoody, known for her fierce independence, was first elected MP for Exeter in 1966 and had been member for Crewe and Nantwich since 1983. Her death will trigger a by-election in the safe Labour seat.

Veteran left-wing politician Tony Benn said Dunwoody was a very distinguished MP who was always listened to with great respect.

During her long parliamentary career, Dunwoody served as chairman of several committees and took special interest in transport, the National Health Service and the arts. She was life president of the Labour Friends of Israel group.

She leaves a daughter and two sons, and 10 grandchildren.