[1] Mansell-Moullin took part in several protests including the 1910 demonstration held in Hyde Park, in which she shared the stage with Emmeline Pankhurst.

[1] After her imprisonment, the CSU was disbanded and a more militant organization, the Forward Cymric Suffrage Union (FCSU), was formed[7] in October 1912.

In 1913 Mansel Moullin became the honorary secretary of the group Sylvia Pankhurst formed to gain the repeal of the Cat and Mouse Act.

[1] That same year, Dr. Mansell-Moullin performed surgery on Emily Davison after she was trampled by King George V's horse at The Derby, though he was unable to save her.

[11] She resigned from her positions in the FCSU in 1916 due to health concerns, though she continued to work in social programs and with pacifist organizations.

In 1931, she chaired the Society for Cultural Relations with the USSR and worked as a volunteer at St Dunstan's, which operated a home for blind veterans.