Although her Welsh parents lived in London, her mother returned home to allow Laura Mountney to be born in Wales at her grandmother's home, 31 Station Terrace, in Dowlais, Merthyr Tydfil. She was raised in a civil service family as a Strict Baptist. The chapel she attended in Dowlais (Hebron) was Welsh language and although she could not understand it, she loved it, especially the singing. Educated at Marshall's School in Merthyr Tydfil until 1932, she was then sent to the Elmwood School, Croydon. She was evacuated back to Wales aged 13, but with so many World War II evacuees there were no school places left and she attended Aberdare Secretarial School.