Joan Hannington was a real life villain and member of the British criminal elite for over a decade. She was indeed renowned as a diamond thief and did serve time in prison - but that was actually for cheque book fraud, not theft.
Dedicated to Martin Maynard who worked in the Props Department during initial production of the series.
At the time the series is set a single unset diamond of reasonable quality would typically retail for up to £750 assuming they are one carat stones
The show stars Sophie Turner, of Game of Thrones fame, where she played Sansa Stark. Game of Thrones star Stephen Dillane, who played Stannis Baratheon, is the father of actor Frank Dillane, who stars alongside Turner in this film.
It typically takes two to three days to pass something swallowed through to your stools, and can't be hurried - so Joan would have to have lodged on the sofa for more than an evening, however much olive oil she consumed!