Nicholas Elliot, famous MI-6 spy and Kim Philby's foil, wrote with a MB (source: Ben Macintyre's recent history, "A Spy Among Friends"). He rolled the pen between his fingers or on a hard surface as a distraction and to cover his own nervousness during the confrontation with Philby in Beirut.
Famous people's pens
Posted 01 September 2014 - 11:22
In addition to the Lamy and the TWSBIs mentioned earlier, I have also seen him use a Pilot Custom 823. In this video you can see it close at 0:31 and refilling at 0:51. Pretty sure he was using the same when I went to have my copy signed in NYC.
And what looks like a pre 2010 bottle of Montblanc Bordeaux, maybe Sepia.