| Daniel Rigby | Jamie Salter |
| Chloe Pirrie | Gwendolyn Harris |
| Jason Flemyng | Jack Napier |
| Tobias Menzies | Liam Monroe |
| Christina Chong | Tamsin |
| James Lance | Conor Simpson |
| Ed Gaughan | Shaun |
| Kenneth Collard | Jim |
| Michael Shaeffer | Roy |
| Pip Torrens | Philip Crane |
| David Ajala | Jeff Carter |
| James Richard Marshall | Monroe's Campaign Agent |
| Jack Monaghan | Hustings Host |
| Louis Waymouth | Simon Finch |
| Daniel Tatarsky | Returning Officer |
| Michael Webber | MP Selection Committee 1 |
| Abigail Thaw | MP Selection Committee 2 |
| Bruce Mackinnon | MP Selection Committee 3
(as Bruce MacKinnon) |
| Amber Anderson | Sara |
| James Howard | Reporter |
| Charlotte Longfield | Shopper |
| Sarah Hoare | Woman with Pushchair |
| Shawn Aldin-Burnett | Passer-by
(uncredited) |
| Marco Flammer | Biohazard Agent
(uncredited) |
| Robby Haynes | Waldo App Man
(uncredited) |
| Chonradee Kulthap | Laugher
(uncredited) |
| Teresa Mahoney | Floor Manager
(uncredited) |
| Stuart Matthews | Crowd Member
(uncredited) |
| Mia Mills | Audience Member
(uncredited) |
| Angus Powell | College Lecturer
(uncredited) |
| Mick Slaney | Film Crew
(uncredited) |
| Peter Theobalds | TV Crew
(uncredited) |