It is the only dormouse native to the British Isles , although the edible dormouse ( Glis glis ) has been accidentally introduced to the British Isles and has an established population ) . In British sources , it is normally called the Dormouse rather than the Hazel ( or Common ) Dormouse . It is the only dormouse native to the British Isles ( though the edible dormouse , Glis glis , has been accidentally introduced and now has an established population ) , and is therefore often referred to simply as the Dormouse in British sources .