Lena May was born in Yorkley, Gloucestershire, in 1915. Educated at Southgate County School. During the Second World War she worked for the Ministry of Information and was assistant editor of British Ally, a newspaper published by the British government for distribution in the Soviet Union.
Jeger was elected to represent Holborn and St. Pancras in the House of Commons in November 1953. She held the seat until the 1959 General Election when she was defeated. Jeger was a staff reporter on The Guardian until being elected in the 1964 General Election.
After retiring from parliament in 1979 she was created Baroness Jeger.