In October 1909, Marsden was arrested with several other members of the Women's Social and Political Union (WSPU) for dressing in full academic regalia and interrupting a speech by the chancellor of their alma mater, demanding that he speak out against the force-feeding of imprisoned suffragist alumni who were on hunger strike. A few months later, she broke into the Southport Empire Theatre and hoisted herself into the cupola, where she waited 15 hours in order to heckle Winston Churchill, who was soon to become Home Secretary, while he was speaking at an election rally. Marsden was arrested with a deputation to Parliament which was widely reported at the time.