In case you were ever wondering about how many series' there actually are of The Thick of It (as I've been pondering why it seemed to leap from series one to series three)...

"The first series was only three episodes. It was successful enough for a second series of three episodes, six months later. All were originally aired on BBC4. All six were subsequently shown as a run on BBC2, then followed by a DVD, "The Complete First Series". Then the specials, followed by their dvd release, then series three (now 8 episodes), followed by its DVD release; and now this box set.
Perhaps here worth mentioning that an eight-episode series four has already been commissioned and is due for recording and broadcast later this year..."

Thanks for that Play.com