| Name | Character | Episodes |
|---|---|---|
| Ralph Ineson | Chief Constable Ziegler | 6 |
| Anna Maxwell Martin | Lucy Betts-Taylor | 6 |
| Sophie Willan | Holly Pinder | 6 |
| Gerran Howell | DC Simon Evans | 6 |
| Dorothy Atkinson | DCS Carol Shaw | 6 |
| David Mitchell | John 'Ludwig' Taylor | 6 |
| Izuka Hoyle | DS Alice Finch | 6 |
| Derek Jacobi | Mr. Todd | 1 |
| Karl Pilkington | DI Matt Neville | 1 |
| Amanda Lawrence | Julie Tate | 1 |
| Felicity Kendal | Lady Camilla Bryce | 1 |
| Jamie Beamish | Ben Naylor | 1 |
| Flip Webster | Mrs. Bowen | 1 |
| Ella Bruccoleri | Megan Rowlands | 1 |
| Paul Chahidi | Adrian Tate | 1 |
| Rose Ayling-Ellis | Ms. Freya Chordwell | 1 |
| Julie Dray | Tanya | 1 |
| Josh Bolt | Adam Newsum | 1 |
| Tom Bell | Peter Williams | 1 |
| Sam Swainsbury | Mr. Bishop | 1 |
| Naveed Khan | Noel | 1 |
| Bridgitta Roy | Becka | 1 |
| Alice May Feetham | Hannah Waldron | 1 |