| Name | Character | Episodes |
|---|---|---|
| Robson Green | Dr Tony Hill | 30 |
| Mark Letheren | DS Kevin Geoffries | 30 |
| Simone Lahbib | DI Alex Fielding | 20 |
| Hermione Norris | DCI Carol Jordan | 14 |
| Pip Torrens | 3 | |
| Sally Edwards | Kate Lloyd | 3 |
| Bill Thomas | Jack Rowland | 2 |
| Jack O'Connell | Jack Norton | 1 |
| Siobhan Finneran | 1 | |
| Adjoa Andoh | Celeste Davies | 1 |
| Christopher Fulford | 1 | |
| Kenny Doughty | 1 | |
| Michael Maloney | 1 | |
| Mark Bonnar | 1 | |
| Tony Maudsley | 1 | |
| Mary Healey | 1 | |
| Dean Andrews | 1 | |
| Sara Stewart | 1 | |
| Stanley Townsend | 1 | |
| Anton Valensi | 1 | |
| Michael Cochrane | 1 | |
| Bill Thomas | Paranoiac Neighbour (uncredited) | 1 |
| Nicholas Sidi | 1 | |
| Kriss Dosanjh | Anil Vora | 1 |