Iain Glen is only a film actor.
Iain Glen ( born 24 June 1961 ) is a Scottish film , television , and stage actor . Other notable roles include John Hanning Speke in Mountains of the Moon , Sir Richard Carlisle in Downton Abbey , the title role in Jack Taylor and Jarrod Slade in Cleverman . Mountains of the Moon is a 1990 Rankcolor theatrical film depicting the 1857 -- 58 journey of Richard Francis Burton and John Hanning Speke in their expedition to Central Africa -- the project that culminated in Speke 's discovery of the source of the Nile River .