I am now on to the 3rd series of this show and I have to say it is becoming more compelling. Initially, i was unsure of this and felt that it lacked real substance, but it would appear my skepticism was a little unfounded. Firstly, the acting has greatly improved among the main stars since the show first began, coupled with continuing lay complex relationships, and they are far more whole and convincing. The story lines are also becoming more interesting as the arcs grow longer and it becomes less repetitive than the early series', plus the continued introduction of characters that will appear again in later series'.In addition, the slightly darker feel adds a touch of edge, moving it closer to Dr Who in tone, still with plenty of laughs, but a bit more bite. Finally, the budget also seems to have improved as the SFX seem far more convincing. Great fun for all ages, a rarity in modern TV.