Question: Who directed the 1999 warm film starring the English actor who also portrayed a British Army Colonel in Christopher Nolan's action-thriller "Dunkirk"?
Sentence (from "The Trench (film)"): The Trench is a 1999 independent war film directed by William Boyd that portrays a group of young British soldiers on the eve of the Battle of the Somme in the last 48 hours.
Relevant evidence: Yes