|Directed by||Val Guest|
|Produced by||Val Guest|
|Written by||Val Guest|
|Based on||Pillars of Midnight by Elleston Trevor|
|Music by||Stanley Black|
|Edited by||Bill Lenny|
|Distributed by||Rank Organisation (UK) Twentieth Century-Fox(US)|
Commencing on New Year’s Eve in the city of Bath, Dr. Steven Monks (Richard Johnson) diagnoses a mystery patient as being infected with smallpox and sets in motion a citywide quarantine to contain the outbreak. His commitment to the task is affected by the deterioration of his marriage to ex-nurse Julie (Claire Bloom) following his clandestine affair with a family friend.
Monks receives an unexpected blow when the disease strikes closer to home than anticipated and Julie is diagnosed as having contracted the virus. The medical team gradually contain the outbreak until only one unidentified case remains.
The search narrows the identity of final carrier down to Ruth Preston (Yolande Donlan), the woman with whom Monks had been having an affair and the wife of his close colleague Clifford (Michael Goodliffe). She’s eventually traced to a deserted house where she’s sheltering, lonely and desperately ill.
- Claire Bloom as Julie Monks
- Richard Johnson as Steven Monks
- Yolande Donlan as Ruth Preston
- Cyril Cusack as Father Maguire
- Michael Goodliffe as Clifford Preston
- Mervyn Johns as Buckridge
- Kay Walsh as Matron
- Norman Bird as Harold Davis
- Vanda Godsell as Agnes Davis
- Basil Dignam as Medical Officer
- Arthur Christiansen as Editor
- Ray Barrett as Bennett
- Andrew Crawford as Dr. Ruddling
- Jill Curzon as Nurse Jill
- Ursula Howells as Joanna Duten
- Basil Dignam as Medical Officer Boswell
- Arthur Christiansen as Mr. Graney
- Ray Barrett as Health Inspector Bennett
- David Weston as Brian Davis (uncredited)
- Pauline Barker as Clara (uncredited)
- Joby Blanshard as Health Inspector Matthews (uncredited)
- Felix Bowness as Wellford (uncredited)
- Olwen Brookes as Senior Nursing Officer (uncredited)
- Victor Brooks as Health Inspector Collins (uncredited)
- Gerald Case as Chief Administration Officer (uncredited)
- Norman Chappell as Welford (uncredited)
- Rachel Clay as Jane Davis (uncredited)
- H. Leonard Coggins as Waiter (uncredited)
- Richard Coleman as Scott James (uncredited)
- Maureen Crombie as Auxiliary Nurse (uncredited)
- Monti DeLyle as Night Porter (uncredited)
- Marian Diamond as Sister Durrell (uncredited)
- Suzan Farmer as Carole (uncredited)
- Leonie Forbes as Nurse Vicky (uncredited)
- Stewart Guidotti as Sidney Davis (uncredited)
- Alan Keith as Health Inspector Sanders (uncredited)
- Bruce Lewis as Himself - TV Reporter (uncredited)
- Peter Madden as Ambulance Driver (uncredited)
- Terry Martin as Guildhall Sergeant (uncredited)
- Carmel McSharry as Cleaner (uncredited)
- John Merivale as Mr. Bradley (uncredited)
- Graham Moffatt as Fat Man in Vaccination Line (uncredited)
- Bruce Montague as Brooks (uncredited)
- Ian Parsons as Health Inspector (uncredited)
- Lisa Peake as Nurse Lisa (uncredited)
- David Rose as Health Inspector (uncredited)
- Guy Thomas as Himself - Newsreader (uncredited)
- Kim Tracy as Daphne Davis (uncredited)
- Russell Waters as Town Clerk of Bath (uncredited)
- Joseph Wise as Deputy Health Minister (uncredited)
- 80,000 Suspects on Internet Movie Database
- British Movie Directors  Retrieved 2010-03-11.
- Original Clip from film  Retrieved 2010-03-11.
- Opening scenes Clip from film  Retrieved 2010-03-11.
- Visit Bath - Movie Locations in the City Page 4[permanent dead link] Retrieved 2010-03-11.
- Val Guest - Obituary, 15 May 2006 - The Independent  Retrieved 2010-03-12.