• title card: SQUARE ROOT OF EVIL superimposed on a reel tape recorder (recreated by Richard McGinlay)

Series 1 - Episode 3
Square Root Of Evil

by Richard Harris

Production completed: 21 January 1961. First transmission: 21 January 1961

Steed impersonates the forger Riordan, which allows him to join a crime syndicate that prints forged banknotes. Having uncovered their plans, he finds his every move being watched by The Cardinal - the second-in-command. Only the pretence of an injury eventually allows Steed to visit his Doctor's surgery and Keel ensures that The Cardinal and his superiors, Bloom and Hooper are arrested.


Teleplay by Richard Harris regularThe SaintAdam AdamantPolice SurgeonThe Sweeney
from a story by John Bryce regular
"The Avengers" Theme composed and played by Johnny Dankworth regular
Designed by Patrick Downing regular
Story Editor John Bryce regular
Producer Leonard White regularCallanPolice Surgeon
Directed by Don Leaver regularCallanPolice Surgeon
Production Assistant Barbara Forster regular
Floor Manager Geoff Smith regular
Stage Manager Nansi Davies regular
Call Boy unknown
Lighting Director Peter Kew regular
Operational Supervisor Peter Wayne regular
Senior Cameraman Michael Baldock regular
Sound Supervisor Peter Cazaly regular
Vision Mixer Del Randall regular


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