James McAvoy character Brian Jackson
Alice Eve character Alice Harbinson
Rebecca Hall character Rebecca Epstein
Catherine Tate character Julie Jackson
Dominic Cooper character Spencer
Benedict Cumberbatch character Patrick Watts
James Corden character Tone
Mark Gatiss character Bamber Gascoigne
Guy Henry character Dr. Morrison
John Henshaw character Des
Elaine Tan character Lucy Chang
Simon Woods character Josh
Charles Dance character Michael Harbinson
Lindsay Duncan character Rose Harbison
Sule Rimi character Marcus
Ian Bonar character Colin
Nicholas Gleaves character Speaker for Nuclear Disarmament
Joe Van Moyland character Hippy at Party
James Gaddas character Martin Jackson
Joseph Friend character Young Brian
Rasmus Hardiker character University Challenge Competitor
Robert Cawsey character University Challenge Competitor
Ben Willbond character University Challenge Coordinator
Su Eliott character Cleaner
Reuben-Henry Biggs character Anthony Salmon
Bethan Bevan character Cordelia Sykes
Tom Allen character Tristram Neville
Raj Ghatak character Nigel De Havilland
Kenneth Hadley character Television Director
Gerard Monaco character Waiter