Ada Mullins

The Unicorn was a female cockney master thief who was responsible for a number of jewel thefts at country houses. She assumed the identity of Robina Redmond 'the absolute hit of the social scene' in order to stay at Clemency Eddison's house. The Unicorn went after Clemency Eddison's Firestone, but was foiled by Agatha Christie, however in all the confusion she escaped and travelled back to London. (DW: The Unicorn and the Wasp)