It's an open secret that the character of Malcolm Tucker (played by Peter Capaldi) in In the Loop is based on Tony Blair's main advisor, Alastair Campbell.
In March, just before the movie opened in the UK, Campbell watched the movie and discussed it with critic Mark Kermode for BBC2's The Culture Show.
Oddly enough, Campbell isn't flattered by the portrayal. Go figure. Though he did laugh at the "Shitting Forecast" joke.
Alastair Campbell writes about the circumstances of this viewing and interview.
Also, The Onion AV Club has a long and wide-ranging interview with Armando Iannucci. The whole thing is worth reading. Here's one exchange of interest:
AVC: In that case, it’s almost more poignant than funny, because the abruptness just increases how pathetic it is.
AI: I wanted this to be about people who are several rungs down, and all the decisions are being made through there. The guy I met from the CIA said he spent his first year at the CIA doing desk paperwork, and dreaming that someone would tap him on the shoulder and say, “Listen, you’ve done very well, we’re going to move you through that door and show you the real CIA. Go through there, that’s where all the big screens are, all the equipment and the surveillance.” It never happened. There is no “over there.” It’s just this. Marker pens. He said they got a lot of their intelligence from the Baghdad newspapers, because they were actually more accurate than what they were getting back from their operatives.