 The BBC's Head of Drama, Michael Barry, felt that Cartier's English dialogue was not quite right, and assigned Nigel Kneale — a staff writer who had been working at the BBC since the previous year — to improve it, with Cartier's approval.Officially credited for "additional dialogue", this was Kneale's first major television drama credit.The drama starred Robert Harris, Howard Lang, Esmond Knight, Leonard White and Donald Pleasence, and was transmitted live from 9–10.40pm on the evening of Sunday 20 July 1952.