As I type this, a block away from my flat, under the austere and glowering gaze of the mighty Senate House, they're filming the new Batman movie (called Batman Begins, aka The Intimidation Game, which was what was actually written on the papers stuck on the windscreens of the crew's numerous trucks).
I didn't see any of the glittering cast (dir. Christopher Nolan, Christian Bale, Michael Caine, Gary Oldman, Katie Holmes, Morgan Freeman, Rutger Hauer etc.) though I did see plenty of replica US police cars with Gotham Police Department insignia on the side. Rather incongruous in genteel Bloomsbury, I can tell you. I got stopped from taking any proper photos, so only managed to sneak off this quick Nokia-cam one indicating the production staff trying to film without closing the streets down.
According to a decent post by Kris Tapley half-way down this otherwise chaff-heavy thread at an IMDB messageboard, Nolan is a big fan of Blade Runner's non-CGI effects - hence the importance of period architecture presumably. I think he's picked a good 'un - Senate House would seem to be a perfect stand-in for a faux-'30s monolithic US police department building.
Senate House's mythology is already greater than that conjured by its awesome physical presence, reputed to be the model for Orwell's Ministry of Truth in his 1984 (as noted previously) - and it's frequently a host for scurrying film crews, though I haven't spotted it in a film or TV thus far. And so now it appears to be part of a Raymond Hood-inspired alternative New York too (as 'Gotham City'). Simulacrum indeed. It's interesting to ponder that a chunk of London's fabric gets used to conjure this exaggerated unreal New York - somehow London becomes another chapter in New York's Celluloid Skyline.