Ethel Margaret Mills was born in West Derby on 31st March 1909 to Albert and Margaret Mills (née Whalley). They lived at 12 Freehold Street for most of her childhood. Margaret's mother suffered from chronic TB and had to spend prolonged periods at the Cleaver Sanitorium in Heswall, (a hospital built specifically to help people recover from TB or 'consumption'). Her mother passed away when Margaret was just 11 years old, leaving her to look after her father until he re-married in 1924. Albert's second wife was Marie Morris, who had been his first wife's health visitor and they later had a child together - Pauline Alexandra Mills, born in 1928.
Margaret attended the Liverpool Institute High School for Girls, situated at Blackburne House, Faulkner Street and after matriculating in 1926, she came to work as an assistant at Burrell & Hardman aged just 17. Edward Chambré Hardman was friends with Miss Ashwell, the headteacher of Margaret's school and he asked her whether she had any girls interested in photography who were due to matriculate, who could come and work in his studio as an assistant. Miss Ashwell recommended Margaret for the role and she quickly gained responsibility and trust within the business, to the extent that Hardman left Margaret in charge of the studio in his absence.
In 1927 Edward and Margaret begin to write to each other and although at first their language is very formal, by 1928 there is evidence of a more personal relationship. Hardman gives Margaret the nickname "Tweeka" and they often refer to themselves in the third person - which they continue to do for the rest of their relationship.