Robb was born in Plymouth on Christmas day in 1913 and likely joined St Swithun's around 1924. After finishing at the school, she went to Bedford College in London which was the first higher education college for women in the UK. After this she moved to Cape Town and started working at St. Cyprians School as a teacher. 

Robb was one of the founding members of the Black Sash movement in Cape Town in August 1955, an organisation instrumental in protesting against apartheid and providing marginalised groups, specifically women, with basic necessities such as food and clothes, as well as support.

In 1960 the Sharpeville massacre occurred after 7,000 people protested against anti-black pass laws, these laws severely restricted the movements of black people. The South African Police opened fire on the crowd when they started advancing towards the police station, 69 people were killed and 180 were injured. After the massacre Robb and other activists brought supplies to people in the area and also helped them to visited their loved ones in prison.

After the creation of Khayelitsha which was a township purposely created to segregate black people in Cape Town, Robb would visit the people who were forcefully relocated there and assisted them with legal problems. In 1989, she was elected as honorary life Vice President of the Black Sash in honour of her leadership and dedication to the organisation.

Robb died in January 2009 at the age of 95 leaving behind five children, thirteen grandchildren and thirteen great grandchildren.