That's Tony Robinson. He played Baldrick in "Black Adder" with Rowan Atkinson. Tony also presented the 20 year British series "Time Team", and regularly does new historical programs.
That’s the guy.
http://www.freerepublic.com/focus/chat/3713251/posts?page=5#5
https://www.youtube.com/watch?v=SG4Ec9nEwwk