Born as Emily May Triggs, the daughter of Stephen and Sarah Triggs, she was educated at Prenton and Huntingdonshire College. At the age of 18, she joined the Women's Auxiliary Air Force and served as an air traffic control assistant between 1955 and 1959.
From 1977 to 1989 Blatch was a councillor on Cambridgeshire County Council and was council leader. She was created Baroness Blatch, of Hinchingbrooke in the County of Cambridgeshire on 4 July 1987. From 1991 to 1994, she was Minister of State for Education and Minister of State for the Home Office from 1994 to 1997.