Who is Major Dexter Smythe (Octopussy) from Octopussy and what is their importance?

After a lifetime of self-indulgence and tropical sloth, Major Dexter Smythe, OBE, Royal Marines (Retd), has become a shadow of his former self. He used to be a handsome military officer who made easy sexual conquests with the servicewoman with whom he came into contact, but now, after suffering from two coronary thrombosis incidents, he is in final stages of dipsomania. In 1941 he had volunteered to be seconded from the Royal Marines to Combined Operations Headquarters under Mountbatten.