Mastering British Politics by F. N. Forman. It's quite dry, actually, and he's not really saying it's all wank, that's exaggeration on my part but some bits he readily admits the political system has its flaws, like regarding public's disinterest or politicians' capabilities etc etc. He basically goes "Is this good/efficient/commendable? Not really, no and it probably won't be." at a lot of things.