Ian Hart (born Ian Davies; 1964) is an English actor. He is perhaps best known for his roles as Rabbit in the Channel Four drama miniseries One Summer (1983), Joe O'Reilly in the biopic Michael Collins (1996), Quirinus Quirrell in the fantasy film Harry Potter and the Philosopher's Stone (2001), and Kester Gill in the E4 series My Mad Fat Diary (2013–2015).
Hart was born Ian Davies in the Knotty Ash district of Liverpool, one of three siblings, and was brought up in a Catholic family. He attended Cardinal Heenan Catholic High School in Liverpool's West Derby suburb and was a member of the city's Everyman Youth Theatre in his teens, before studying drama at the now-defunct Mabel Fletcher College of Music and Drama. From 1988 to 1991, Hart studied video production at South Mersey College (now part of Liverpool Community College).
Hart portrayed a POUM militia volunteer in the Spanish Civil War in Land and Freedom (1995) and an unemployed Liverpool shipyard worker in Liam (2000). His best known role, however, is perhaps that of Professor Quirrell in Harry Potter and the Philosopher's Stone (2001). He also provided the voice of the CGI-generated face of Lord Voldemort.