[citation needed] During the First World War, Horsbrugh pioneered a travelling kitchen scheme in Chelsea, London, which gained sufficient renown as to warrant an invitation to bring the kitchen to Buckingham Palace one lunch hour to entertain Queen Mary, who approved particularly of the sweets.

[1][4][5] In 1936 she became the first woman to move the Address in reply to the King's Speech, following which she was interviewed for television, in the process becoming the first member of parliament to appear on that medium.

[6] She unsuccessfully contested Midlothian and Peebles in 1950 and was elected in the delayed poll at Manchester Moss Side, sitting from 1950 until her retirement in 1959.

[7] As Parliamentary Secretary to the Minister of Health, 1939–45, she was responsible for arranging the evacuation of schoolchildren from major cities during the war.

Horsbrugh also carried out a great deal of preparatory work on the scheme which eventually became the National Health Service.