From Wikipedia
Moira Lynd was a British stage, television and film actress.
During the 1930s she became a leading lady in British quota quickies.
She made her last film in 1940, but made several television appearances in the post-war era.
When 'Gentleman' Burton boards the Capri his aura of mystery makes the crew curious about his origins and makes him especially attractive to the Captain's daughter. But he little realises the danger that is to unfold when the Captain conceals diamonds on board as a favour...