The actor in question has a strong, very-RP English accent and somewhat (but not noticeably) nasally voice. The highest-profile role I could find him in was dubbing Umberto Orsini in Luchino Visconti's The Damned (a.k.a. La caduta degli dei). It's notable because it's a big-budget, major studio film, and he appears to be the only member of the main cast to be re-dubbed by someone else (presumably because of his IRL accent.)
Here's a link to the movie on YouTube, at 4:58 there's an exchange between him and Charlotte Rampling, and you can clearly hear his voice (https://youtu.be/f7p_xwxzjDQ?t=299).
What's odd is that I can't recall hearing that particular VO in many other English-dubbed Italian films, even at this period. The only other one I could find is the 1979 Umberto Lenzi film From Hell To Victory, (Contro 4 bandiere) where he dubs the voice of Jean-Pierre Cassel. (link: https://www.youtube.com/watch?v=ZMc5Rjy ... oDetective)
Any help identifying this VO would be greatly appreciated.
