High Tide was a novel published by P.M. Hubbard in 1971. Almost a decade later, the story was adapted for the Armchair Thriller television series in four episodes, and I recently watched, the complete mystery on Talking Pictures. Benefiting from a strong cast, it's stood the test of time pretty well, even if by modern standards the background music seems very intrusive.
Hubbard is a writer who has been recommended to me by several good judges, but I've not read much of his work. In my shallow youth, I was deterred partly because he has a very low-key style, and wasn't especially interested in complex plotting, and partly because his main interests, such as small boat sailing, didn't coincide with mine. But I've come to appreciate his qualities more, and I intend to read him more extensively.
High Tide is an atmospheric thriller rather than a complex puzzle, but it does feature a neat variation on the "dying message clue". Curtis (Ian McShane, at his best in this role) has just been released from prison after serving a sentence for manslaughter. He was responsible for the death of a man called Maxwell, whose mysterious final words prompt a rather menacing chap (played by Terence Rigby) to pursue him. Curtis figures out the meaning of the message,and befriends a pretty but mysterious young woman as he tries to find out what Maxwell was up to.
His quest - undertaken by boat, in characteristic Hubbard fashion - leads him to a house occupied by an ill-matched couple, played by John Bird and the glamorous Kika Markham, who seem to have the clue to the mystery. The sequence in which Rigby's character gets his come-uppance is rather memorable. I enjoyed seeing this, and it's helped to strengthen my interest in Hubbard..