It's part of the Helvetica family closest I could match was Neue Helvetica Bold Extended but on the Mk3 badge it's been squashed vertically slightly so that's either what they did or it was a custom commissioned font.
http://www.linotype.com/13111/neuehelvetica73boldextended-font.html
http://www.linotype.com/13111/neuehelvetica73boldextended-font.html