Just watching the brilliant Sherlock A Scandle in Belgravia and it reminded me of a series on tv in the late 70s early 80s . For the life of me can't remember what it was called but I believe it was a BBC three parter . It involved a seedy courier given a task of transporting a hatbox that he was told not to look into. I remember it involved politicians and the royals And he was in a no win situation out of his league. Any idears ? Not to helpful I know but might ring a bell.