Villain (which also features Ian MacShane, in less leathery form) has Richard Burton as a Kray-alike by way of
White Heat.
Sean Connery's nonce-hating copper in
The Offence touches on many on the moods and tones other films mentioned in this thread feature, without being itself a 'gangster' movie.
Stanley Baker's mid/late sixties Great Train Robbery analogue,
Robbery, is a bridge between earlier, gritty British crime dramas like his own
The Criminal and subsequent, more self-consciously fun caper flicks like
The Italian Job. That film's Charlie Croker (also of
Get Carter) Michael Caine, made the journey back to the seedier seam of gangster movies in 2000's
Shiner, in which he ekes out a similar - but more sympathetic - character to his turn in
Mona Lisa.
Get Carter's directer Mike Hodges returned to the limelight with the noirish
Croupier in 1998; he followed it up with the bleak, and more explicitly gangster-orientated
I'll Sleep When I'm Dead five years later, again featuring Clive Owen as his antihero.
Finally, consider
Shooters, a film by Dan Reed which originated in his desire to make a documentary about real life gangsters in Liverpool, but which instead evolved into a semi-improvised piece of fiction on the same topic, starring many of the men he had met during his research into the subject - steroidal 'door men' and the like.
