Thinking about The Trial again, and I was fortunate to see it again fairly recently, two questions came to me:
Did Terry Gilliam see The Trial before he made Brazil?
Did Patrick MacGoohan see The Trial before he made The Prisoner?
Visually The Trial is absolutely distinctive, one of the few movies that you could recognize from virtually any frame. Tony Perkins is of course perfect casting for Josef K, and he actually acts the part as opposed to falling into the Tony Perkins impression with which he earned his living later on (in Murder on the Orient Express, for example). The rest of the cast is good as well (Jeanne Moreau as Miss Burstner, Welles as Hastler the Advocate, Akim Tamiroff as Block), but the film succeeds or fails on Perkins and he carries it off.
Second billing behind Perkins should probably go to the sets. Unlike Gilliam's Brazil, Welles didn't have the budget to build anything, but he found some amazing locations in several different countries, mostly emphasizing both towering size and labyrinthine confusion. The main location he used was the Gare d'Orsay, a deserted railroad station in Paris which has since been turned into a museum.
The Trial is much more directly comparable to Brazil than The Prisoner, but both comparisons are interesting. In contrast with Brazil (and Kafka, for that matter), K is defiant to the end. He is doomed, but he dies on his own terms.
The Prisoner is more like the flip side of The Trial. Rather than sets and people being overtly threatening and ominous, MacGoohan takes a type of setting that is extremely sunny and familiar (at least to English audiences) and makes it threatening by adding just a few jarring notes of incongruity. And, of course, Number Six is always unbending (unlike Josef K, who always seems to feel as if he might possibly be guilty of whatever it is he's being accused of), and finally is more or less victorious.
In any case, The Trial is one of Welles' best films, definitely worth seeing.