Martin as an M-type character, and David as the typical real-life MI-agent. The type that leaves important top-secret documents on trains (or laptops in hotel lobbys) in sketches from the short-lived, one-series-only sketch show 'Bruiser' (2000) starring Olivia Colman, Martin Freeman, Matt Holness, Charlotte Hudson, David Mitchell and Robert Webb.

Oh, isn't it cute? John is playing Mycroft for a day. Complete with brolly. =D

Clip is from episode 5