I think my main problem with this was the casting of Richard Burton as the titular gangster, clearly based on a composite of the Kray twins.
Burton doesn't really seem suited to playing a criminal psychopath, and the bad cockney accent is just the start of it.
Maybe this was around the time he was rumoured to be drunk during entire shoots (probably an exaggeration, but he does seem a little detached in certain scenes).
The script by Dick Clement…