Subtle little gags in the dialogue
I've taken to watching Frost from the beginning, in the last few days, and noticed every now and then the odd subtle gag thrown in, usually for Frost, but I've just started watching S02E02 (Widows and Orphans), and there's this little exchange between Mullett and the DCI (Jim Allen?)
It goes something like this:-
Mullett: How about this pornography business?
DCI Allen: Ah we're very near. By the end of the week I'll be giving them a pull.
I can't believe somebody wasn't grinning like a Cheshire cat when they wrote that.