It is a principle of English law that the actus reus and mens rea must coincide. That is they must happen at the same time. This is sometimes referred to as the contemporaneity rule or the coincidence of actus reus and mens rea. See:
Edwards v Ddin (1976) 63 Cr App R 218 Case summary
However, the courts often apply a flexible approach in holding that the actus reus is a continuing act. See: