- Writer:
- Patrick Alexander
- Theme music composed by:
- Don Harper
- Script Editor:
- Anthea Browne-Wilkinson
- Designer:
- Chris Pemsel
- Producer:
- Jordan Lawrence
- Director:
- Raymond Menmuir
- Cipher clerk:
- John Scholes
- Frank Smith:
- Robert Urquhart
- Controller:
- James Cossins
- Joan Grant:
- Heather Canning
- Special Branch sergeant:
- Fred McNaughton
- Special Branch constable:
- Brian Vaughan
- Alice Campbell:
- Alethea Charlton
- Chief Supt. Shepherd:
- Michael Bates
- Blake:
- James Drake
- Armstrong:
- John Humphrey
- Minister of State:
- John Wentworth
- Michael Grant:
- Robert Lang
- Lusaka:
- Cllfton Jones
- Lusaka's secretary:
- Louis Mahoney
- Special Branch man:
- Patrick Connor
- Woman detective:
- Valerie Bell
- Special Branch detective:
- Max Latimer
- Van driver:
- John Caesar
- Sergeant Clifford:
- Philip Anthony
- Guard:
- Alan Travell