Jacobi, an only child, was born in Leytonstone, London, England, the son of Daisy Gertrude (née Masters), a secretary who worked in a drapery store in Leyton High Road, and Alfred George Jacobi, who ran a sweet shop and was a tobacconist in Chingford [REF].
While in the sixth-form, he starred in a production of Hamlet, which was taken to the Edinburgh Festival Fringe and very well regarded [REF].