Little Dorrit didn't receive the critical acclaim in the UK that was expected, perhaps because it was being shuffled to different time slots (even at the last minute) and the half hour serial broadcasts. Previously the BBC said it would probably step away from making period dramas.
However, with the format that PBS is adopting (showing Little Dorrit in longer segments on a weekly basis) and the the rave reviews in the US, BBC is rethinking this idea. From the Telegraph's interview with Ben Stephenson, controller of BBC drama commissioning:
Also still important to the BBC, says [Ben] Stephenson, is period drama. Reports that Auntie is to abandon her bonnets are, he says, wide of the mark. “We are really pretty much the only place in the world that makes this kind of drama – the reviews of Little Dorrit in America at the moment are quite extraordinary,” he explains.