| Name | Character | Episodes |
|---|---|---|
| Natalie Dormer | Sarah Etches | 6 |
| Iain De Caestecker | Paul Roberts | 6 |
| Tom Ellis | Mark Etches | 6 |
| Daniel Kaluuya | Mac Armstrong | 6 |
| Robbie Gee | DCI Armstrong | 6 |
| Joe Dempsie | John | 6 |
| Claire Rushbrook | Meg Roberts | 6 |
| Lily Loveless | Anna Roberts | 6 |
| Sophie Wu | Jay | 6 |
| Johnny Harris | Neil Valentine | 6 |
| Jenn Murray | Natalie | 5 |
| Francis Magee | Dr. Tremlett | 5 |
| Theo Barklem-Biggs | DC Firth | 5 |
| Chris Mason | Steve | 5 |
| Eleanor Matsuura | Vicky | 4 |
| Ruth Gemmell | Alice | 4 |
| Ian Hanmore | Polus | 4 |
| Lloyd Hutchinson | Supt. Clement | 4 |
| Craig Conway | Phil | 3 |
| Daniela Nardini | Helen | 3 |
| Sophia La Porta | Tracy | 2 |
| James Greene | Eric | 2 |
| Philip Bird | Mr. Peterson | 2 |