Whilst studying English at Oxford, she made her radio debut singing topical songs at the piano which were featured on Pick of the Week. This led to further appearances as a singer-songwriter with her trio Premier Cru and later as one-half of Casson and the Brannick Academy. Together they have written two CD's including Tutankhamun all Wrapped Up which was distributed to 65 thousand visitors at the 02 Tutankhamun exhibition.
Casson's stage work continues to be inspired by the written word. Her first musical Two Tiger's based on the life and works of pioneering modernist writer Katherine Mansfield was the first by a woman to be a PRS Vivian Ellis Prize finalist. Shows since then include a series of collaborations with Tom Blackmore notably The Happy Prince based on Oscar Wild's short story which has toured nationwide, Requiem, a political review, and Persephone both with words by poet Simon Rae and most recently song cycle Dreams of Peace & Freedom, that draws on poetry that inspired Nuremberg prosecutor and human rights champion David Maxwell Fyfe, to tell the story of the birth of human rights in Europe after the Second World War.