Tanner was born in 1876 in Bath, the eldest of seven children of Samuel Thomas Tanner (1849-1929), of 6, Leigh Road, Clifton, Bristol, a coal merchant and magistrate who worked with the Bath Board of Guardians,[1] and Jeanetta ("Nettie") Jane, assistant in a "high-class draper's", and daughter of George Fry, of Lynton, North Devon, sometime grocer, farmer and "post-horse proprietor".

[5] She became a student teacher aged thirteen and spent her time teaching in private schools until she was employed by the Ladies' College, Halifax where she was trained.

Tanner arranged her own education and submitted herself to the University of London where as an external candidate she obtained a first class history degree in 1904.

[7] Nuneaton High School for Girls was founded in 1910 with the strong support of Warwickshire's Director of Education Bolton King.

[citation needed] She was made a dame for her contributions to drafting the Education Act 1944 as she had sat for two years on the Fleming committee which looked at public schools.