[There] is too much of Garfield [in The House of Hanover: England in the Eighteenth Century] and he is showing-off like mad. The first person singular may have appeared in the earlier books, but I recall no instance; Garfield however talks as much about himself as about his characters and in that exuberance of verbiage which is a delight in his novels but which is quite out of keeping here. The smooth continuity of the [Mirror of Britain] series is rudely jarred. He is always readable, but I am not sure that he is believable. (p. 29)

J. Allan Morrison, in Children's Book Review (© 1976 Five Owls Press Ltd.; all rights reserved), October, 1976.