A film by Lord Snowdon and Derek Hart Why do you keep a pet? What do you demand from your dog, your cat, your budgie in return for feeding it and teaching it to be clean about the house? Is it companionship you want? Do you keep a dog to protect you? Is the bird you keep behind bars simply a living ornament or an essential member of the household just like one of the family? The relationships between human beings and animals, particularly domestic animals, are sometimes simple. But often they are as complicated as the relationships that exist between people themselves. Executive producer MICHAEL LATHAM