Morrison was an active member of the Women's International League for Peace & Freedom (WILPF) and was at one stage the chair of its British branch.
It had been hoped to obtain the signatures of one million women against the Second World War, but as Morrison admitted, "The invasion of Scandinavia has, of course, made it much more difficult now to approach people about signing an appeal for negotiations because opinion is hardening against the pacifist.
[7] For the last few years of her life, she shared a house with Myrtle Solomon, who was the general secretary of the Peace Pledge Union and later the chair of WRI.
[8] Other people with whom Morrison worked included Vera Brittain, Alex Comfort, Laurence Housman, Hugh Brock and Kathleen Lonsdale and many other leading individuals in radical politics during much of the 20th century.
She also talked about many others involved in the suffrage campaign, including Emmeline Pankhurst, Dorothy Evans, Grace Roe, Teresa Billington-Greig, and Monica Whately.