Jeffery was born in 1886 in Devon.[1] Her father was J. E. B. Jeffery who worked for the Indian Civil Service.[2][3]
She became active in the women's suffrage movement, and joined the Women's Social and Political Union (WSPU) in 1909. She became a paid WSPU organiser in Newport, Wales.[4]
On 8 December 1910, coincidentally the date of the Feast of the Immaculate Conception, Jeffery was waiting outside Holloway Prison to welcome the release of imprisoned suffragettes.[5] This was common practice for the WSPU at the time. Whilst waiting, Jeffery met Mary Kendall and they discussed the idea of creating a Roman Catholic women's suffrage organization to bring together Catholics, both male and female, to work towards women's suffrage.[6]
Jeffery and Kendall founded the Catholic Women's Suffrage Society (CWSS) in 1911. Jeffery served as honorary secretary and treasurer.[7] It was the only organized group of Roman Catholics in England established to actively and publicly participate in the campaign for women's enfranchisement,[8] and the founders hoped that the organisation would give Catholic women a respectable way of becoming active in the movement.[9] Over time the Society extended its interests and campaigned on other women's issues such as equal pay.[10]
Jeffery died in 1940.[1]