This is a British expression of contempt. The original Barbara Cartland was a British female author who wrote incredibly
predictable, dated chick lit; she was well-known for a number of reasons:-
She had the longest entry in “Who’s Who”;
She believed that, despite her age and decrepitude she was incredibly attractive to the male sex;
Under no
circumstances could she possibly be wrong;
The meaning has now broadened and is used to describe any
pretentious, arrogant, unattractive female with delusions about her looks, talent, knowledge etc. Should you meet one usher her into the nearest padded cell with a forked vermin stick and arrange for NASA to send her on a probe to Jupiter.