| Name | Character | Episodes |
|---|---|---|
| Tom Felton | Thomas | 8 |
| Clive Owen | Ross Tanner | 8 |
| Eddie Marsan | Liam Morrison | 8 |
| Claire Skinner | Catherine Tully | 8 |
| Ian Redford | Skinner | 8 |
| Donald Douglas | Dr. Peters | 8 |
| Frank Harper | DS Finch | 8 |
| Rupert Holliday-Evans | DS Pewsey | 8 |
| Rebecca Egan | Marilyn Tanner | 8 |
| Ben Smith | Sam Tanner | 8 |
| James Greene | Dr. Goddard | 4 |
| Tom Felton | 2 | |
| Art Malik | 2 | |
| Stuart Wilson | Adam Bendrix | 2 |
| Rebecca Hazlewood | 2 | |
| Phoebe Nicholls | Judith Bendrix | 2 |
| Michael Kitchen | 1 |