Mannion carried this one through, with a little help from the idiot aide.
To take a behemoth of a character like MT out of an episode, and still produce a very, very solid episode (even by the high standards of what is, IMHO, the greatest ever sitcom not called "Peep Show") is applaudable.
I generally obviously prefer the New Labour lot, but Mannion is absolute gold for the Tories. Centering the episode on the old dinosaur was a good call.
Three (small) criticisms:
(1) I thought some of the dialouge was a bit meandering at times; especially at the beginning. Not quite as direct as it had been in most of series 1-3.
(2) The two young Lib-Dem coalition guys are a bit vanilla. Not every character can be a MT or a Mannion, but these two didn't really stand out for me.
(3) The Glenn character has taken a slightly strange direction (I'll re-watch tonight, in case I just imagined it).