David John Bradley (born 17 April 1942 ) is an English actor. He is best known for playing Argus Filch in the Harry Potter film series and Walder Frey in the HBO series Game of Thrones, though he is also an established stage actor with a career that includes a Laurence Olivier Award for his role in a production of King Lear. Other acting credits include the BBC series Our Friends in the North, the ITV series Broadchurch, for which he won the best supporting actor award at the 2014 British Academy Television Awards, and the films Hot Fuzz and Captain America: The First Avenger. In 2013, Bradley portrayed William Hartnell, the actor who played the First Doctor, in the Doctor Who drama An Adventure in Space and Time.