David Bradley (born 17 April 1942) is the actor who portrayed Jack Marshall on the first series of Broadchurch. As well as this role, the critically-acclaimed actor is also known for portraying Argus Filch on the Harry Potter franchise (2001-2001), Lord Walder Frey from the HBO series Game of Thrones (2011-present), and William Hartnell - who played the First Doctor - to celebrate the 50th anniversary of Doctor Who, and Professor Abraham Setrakian on The Strain.