Lena Jeger, chair of the Labour Party when it was being infiltrated by Militant Tendency in the late 1970s, has died aged 91.
She was also a London MP in the fifties and later a life peeress.
The daughter of a Post Office sorter, she was educated at Southgate County School and Birkbeck College, London.
In 1948, she married Dr Santo Jeger, who was Labour MP for Holborn and St Pancras South, and when he died in 1953, she succeeded to his seat.
She worked as a civil servant in the Ministry of Information and the Foreign Office during and after World War II.
At the Foreign Office, she learned Russian and was later given the post of assistant editor of British Ally, the paper published by the British Government in Russia at the end of the war and during the first months of peace.
She also served on the old London County Council and was a member of the St Pancras Borough Council.
She was out of Parliament from 1959 to 1964, during which time she worked as a columnist on The Guardian newspaper.
Mrs Jeger served on Labour's ruling National Executive Committee from 1960 to 1961 and again from 1968 to 1980, and was chairman of the party from 1979 to 1980 - during a difficult time for Labour, when she successfully fought to preserve its political status.
Mrs Jeger was a member of the Consultative Assembly of the Council of Europe and of the Western European Union from 1967 to 1971.
She was made a life peeress in 1979. In the House of Lords she served as a front-bench speaker on health and social security.