Doctor Who 's trump card and, if you're looking for evenness of tone, you've come to the wrong show. It's mutability has always been one of its greatest strengths, while at the same time resulting in dramatic lurches in quality (for good or ill) not found in more consistent -- but infinitely duller -- episodic TV. But in the Davies era the good, the bad and the downright bonkers sat cheek by jowl like never before. Never mind the old chestnut about the show's "infinitely flexible format" serving up space opera one week and historical costume drama the next -- in noughties Who , we were asked to readjust our emotional sets on a minute-by-minute basis. For this reason, Davies' big, grandstanding emotional scenes could occasionally feel a little forced, arriving from nowhere, like the jarring chord change in clunky prog rock epic, with only the watering of David Tennant's eye or the swell of Murray Gold's strings to tells us this was one of those moment when we were Meant To Be Feeling Something. The death of Lady Cassandra is a case in point -- after two episodes in which she'd bounced between broad comic parody and mass murderer, all that eulogizing and final, dramatic swan dive just felt like crocodile tears. And where exactly did that whole "Time Lord Victorious" business suddenly spring from in the final reel of The Waters of Mars ? (And where did it go again, for that matter?) On other occasions, things simply