 His mother, Anna Barbara (née George), was a violinist, and his father, Edgar Philip Rathbone, was a mining engineer and scion of the Liverpool Rathbone family.He had two older half-brothers, Harold and Horace, as well as two younger siblings, Beatrice and John.Basil was the great-grandson of the noted Victorian philanthropist, William Rathbone V, and thus a descendant of William Rathbone II.