Though it might seem an obvious move to shoot the Doctor in HD, given that the Torchwood spinoff has had the treatment, there are plenty of technical considerations that have dissuaded the BBC from doing it.
The main issue, according to Julie Gardner, an executive producer for Doctor Who, is that, whereas Torchwood has maybe 10 or 20 special effects per episode, Doctor Who has a hundred or more.
"I think it would take more time for us to do our post-production, and I think it would be more costly. And I genuinely love the look that we've managed to achieve with our [directors of photography] and our grade on 'Doctor Who'," she told The Stage magazine.
So, no HD Doctor yet.
(Via SyFy Portal)