| Name | Character | Episodes |
|---|---|---|
| Herbert Lom | Doctor Roger Corder M. D., D. P. M. | 26 |
| Michael Johnson | Dr. Jimmy Davis | 23 |
| Rona Anderson | Sister Campbell | 3 |
| Lyndon Brook | Mark | 1 |
| John Arnatt | Recorder | 1 |
| Roger Delgado | Wirral | 1 |
| Joan Collins | LIz | 1 |
| Rita Tushingham | Joy | 1 |
| Susan George | Gina McCutcheon | 1 |
| Rosalie Crutchley | Lady Naomi Leigh Brooke | 1 |
| Francesca Annis | Mary | 1 |
| Barbara Shelley | Catherine | 1 |
| Jennifer White | Nurse | 1 |
| Jennifer White | Nurse Jones | 1 |
| Jane Merrow | Penny Branch | 1 |
| Patrick O'Connell | Coalman | 1 |
| Dennis Price | Major Falcon | 1 |
| Tony Steedman | Superintendent Rob | 1 |
| Andrew Keir | Poppa McCabe | 1 |
| Warren Mitchell | 'Deacon' Hobbs | 1 |
| John Stuart | Dr. MacRae | 1 |
| Sonia Dresdel | Agnes | 1 |
| Geoffrey Palmer | Williams | 1 |
| Patricia Marmont | Chelsea Woman | 1 |
| Annette Andre | Jane | 1 |
| Peter Williams | General Sir Ayrland Fielding | 1 |
| Mark Burns | Businessman | 1 |
| Gemma Jones | Pamela Phillips | 1 |
| Richard Johnson | Jimbo | 1 |
| Ian Bannen | Mike Barclay | 1 |
| Robert Beatty | George Shelton | 1 |
| Wanda Ventham | Nurse | 1 |
| Walter Gotell | Swenson | 1 |
| Bernard Lee | Jim Garner | 1 |
| Sylvia Syms | Margo | 1 |
| Ann Firbank | Grace Charlton | 1 |
| Johnny Sekka | Alvar | 1 |
| André Morell | Sir Desmond Shaw | 1 |
| William Marlowe | Peter Anthony | 1 |
| Vladek Sheybal | William Jones | 1 |
| Faith Kent | Miss Gooch | 1 |
| Harold Goldblatt | Darkie | 1 |
| Francis Matthews | Dick Green | 1 |
| John Horsley | Percy Roberts | 1 |
| Jenny Laird | Sarah Hawkins | 1 |
| Flora Robson | Dorothy Wyley | 1 |
| Richard Warner | Sir Harry Branch | 1 |
| James Villiers | Paul | 1 |
| Glynn Edwards | Albert Stokes | 1 |
| Dudley Sutton | Leigh | 1 |
| Adrienne Posta | Hazel Phillips | 1 |
| Michael Ripper | Dublane | 1 |
| Alfred Burke | Sergeant Major Bennett | 1 |
| John Junkin | McCutcheon | 1 |
| Clifford Evans | Mr. Kross | 1 |
| Edward Judd | Tim | 1 |
| Monte Landis | Sid Fiscal | 1 |
| Ray McAnally | Alan Prescott | 1 |
| Ursula Howells | Julia Gray | 1 |
| Ronald Leigh-Hunt | George Hunter | 1 |
| Lloyd Lamble | Basil Phillips | 1 |
| Mark Dignam | Sir Godfrey | 1 |
| Jeremy Spenser | Jan Zapotski | 1 |
| Russell Napier | Headmaster | 1 |
| Roger Livesey | Sir William Bridley | 1 |
| Arnold Diamond | Nathan Blom | 1 |
| Faith Brook | Mrs. Thomas | 1 |
| Tim Seely | Lieutenant Grey | 1 |
| Richard Leech | Captain Maple | 1 |
| Harry Fowler | Heckler | 1 |
| Melvyn Hayes | Bert Morgan | 1 |
| Frederick Piper | Tom Bridges | 1 |
| Zena Marshall | Vera Barclay | 1 |
| Aimée Delamain | Mrs. Oliver | 1 |
| Hamilton Dyce | David Stephens | 1 |
| Edward Evans | Horace Webster | 1 |
| Pauline Yates | Fay Bridges | 1 |
| Eddie Byrne | J. B. Black | 1 |
| Gerald James | Inspector Meredith | 1 |
| Anita Sharp-Bolster | Mrs. Cartwright | 1 |
| Avice Landone | Lady Shaw | 1 |
| Frank Lawton | Geoffrey Petlen | 1 |
| Hana Maria Pravda | Millie Zapotski | 1 |
| Fabia Drake | Mrs. Benthaw | 1 |
| Larry Martyn | Ron | 1 |
| Kay Walsh | Mrs. Kross | 1 |
| Peggy Cummins | Stella | 1 |
| Patrick Whyte | Norman Williams | 1 |
| Robin Hughes | Sir Francis Leigh Brooke | 1 |
| Margaret Lockwood | Jean Forrest | 1 |
| Donald Pickering | Jack Lamond | 1 |
| Blake Butler | Man | 1 |
| Anne Blake | Miss Jones | 1 |
| Jeanne Moody | Eleanor Petlen | 1 |
| Philip Latham | Cooper | 1 |
| Walter Hudd | Carnadine | 1 |
| Julie Stevens | Second Nurse | 1 |
| Christopher Witty | Stone | 1 |
| Peter Bathurst | Sir Laurence Powell | 1 |
| Jeanne Hepple | Miss Thomas | 1 |
| Ronald Hines | Vicar | 1 |
| Megs Jenkins | Dr. Murphy | 1 |
| Joy Shelton | Miss Noble | 1 |
| Ilona Rodgers | First Nurse | 1 |
| William Kendall | Colonel Richards | 1 |
| Henri Vidon | Chairman | 1 |
| Freda Bamford | Doreen's Mother | 1 |
| Beatrice Varley | Clare Bridges | 1 |
| Alan Dobie | Patrick | 1 |
| Harold Berens | Mandelbaum | 1 |
| Avis Bunnage | Mrs. Dineley | 1 |
| Barry Keegan | Hogan | 1 |
| Patrick McAlinney | Scollick | 1 |
| Bryan Coleman | Colonel Mackay | 1 |
| Donald Morley | Inspector Thomas | 1 |
| Margaret Whiting | Angie | 1 |
| Redmond Phillips | Langford | 1 |
| Derek Farr | Frank Hewitt | 1 |
| Leonard Sachs | Henry Gray | 1 |
| John Bonney | Det.-Constable. Cowan | 1 |
| Jeremy Burnham | Robin Gratrix | 1 |
| Hugh Cross | Inspector Riley | 1 |
| June Barry | Honey Benson | 1 |
| Robin Hawdon | Harry | 1 |
| Alfred Maron | Jock Mills | 1 |
| Jack Stewart | McKay | 1 |
| Allan Cuthbertson | Dr. Fisher | 1 |
| Jess Conrad | Danny Pace | 1 |
| John Glyn-Jones | Ensford | 1 |
| Derek Godfrey | Dr. Tate | 1 |
| Rosamund Greenwood | Mrs. Carmody | 1 |
| Joanne Dainton | Paula | 1 |
| Andrée Melly | Gloria | 1 |