| Name | Character | Episodes |
|---|---|---|
| Gerard Butler | Johnnie Donne | 6 |
| Mark Strong | Len Davies | 6 |
| Derek Jacobi | George Cording QC | 6 |
| Nicholas Farrell | Jeremy Crawford | 6 |
| Paul Reynolds | Warren Murray | 6 |
| Helen McCrory | Rose Davies | 6 |
| Peter Vaughan | Michael Colchester | 6 |
| Nina Sosanya | Marica Thomas | 6 |
| Michael Maloney | Peter Segal | 6 |
| Antony Sher | Gerald Lewis QC | 6 |
| Sylvia Syms | Elsie Beamish | 6 |
| Jack Shepherd | Ron Maher | 6 |
| Sarah Louise Young | Jessica Garland | 6 |
| Julie Walters | Emma Watts Q.C. | 5 |
| Jodhi May | Katherine Bulmore | 5 |
| Rory McCann | Derek Hatch | 5 |
| John Lynch | Alan Lane | 5 |
| Roger Allam | John Mallory Q.C. | 5 |
| Anne Reid | June Brierley | 5 |
| Ronald Pickup | Jeffrey Livingstone | 5 |
| Branka Katić | Kristina Bamford | 5 |
| Natalie Press | Lucy Cartwright | 5 |
| Jo Hartley | Ann Skailes | 5 |
| Lisa Dillon | Tasha Williams | 5 |
| Danny Babington | Brian Bundy | 5 |
| Aqib Khan | Rashid Jarwar | 5 |
| Steven Mackintosh | Paul Brierley | 5 |
| Meera Syal | 2 | |
| Abubakar Salim | Sadam | 1 |
| Sarah Hadland | 1 |