I noticwd this when I watched it last night. There are a lot of Britsh actors in Batman Begins (I’m using “British” in the more encompassing sense of “from the British Isles”, meaning England, Scotland, Wales, and Ireland.)
I checked this on the IMDB and there are 15 first billed actors. 9 of the actors are listed as being born somewhere in the British Isles. 6 of the actors are not. Colin McFarlane does not have a place of birth listed, but based on the movies he’s been in I’d say it’s possible he’s British. Rutger Hauer was born in the Netherlands. Ken Wantanabe was born in Japan. This leaves only Katies Holmes and Mark Boon Junior, both of whom were born in Ohio. So out of 15 actors only about 2 are bona fide Americans. Most of the rest are from the British Isles.
I thought this was interesting for a movie sotensibly set in America, with American accents.