David —, actor who played Derek Trotter in BBC TV sitcom Only Fools and Horses (5)
I believe the answer is:
jason
(Other definitions for jason that I've seen before include "Argonaut leader" , "Greek hero, leader of the Argonauts" , "Greek hero, captain of the Argo" , "Boy" , "Leader of the Argonauts who sailed in quest of the Golden Fleece" .)