The Collinson twins first arrived in Britain in 1969.
Madeleine married a British Royal Air Force officer and raised three children.
As is usual in Gothic horror films, the girls spend most of the time sitting around in their nighties; and very nice they look in them too.
Identical twins have been a perennial theme of folklore and literature since Romulus and Remus shrewdly picked up some real estate in what turned out to be Rome.
In fact only one of the sisters is evil, the other is good.
As I mentioned previously, the twins would earn the distinction of being the very first set of twins to ever appear in Playboy.