I'll readily admit to only watching this for the Walter Hill script, which he apparently only wrote the first half of, the rest of which John Huston apologised for in his autobiography. The writing of Desmond Bagley has never intrigued me in the slightest and this is pretty much exactly what I expected from his male oriented adventure/spy novels.
When I think of this period of slow burn espionage thrillers it is inevitable that The Spy Who Came In From The Cold sits as the benchmark for all other films and sadly MacKintosh Man doesn't come close. It's slow all right, and it has a strong thoughtful actor in the lead but this is not Huston's strong suit as a director. Everything is so matter of fact, there's no thrills, no tension, no intrigue, it just goes on and on and on.