Guest Stars Paul Ferris as David Marlowe Colin Gordon as John Alexander Templeton-Green Derek Benfield as The scientist Ronald Hines as Upton James Villiers as Roddy Harrington Martin Wyldeck as Sir Robert Ellacott Jennifer Clulow as Ann Reginald Jessup as Markham Virginia Stride as Sara Charles Houston as Hollins Zeph Gladstone as Scott Georgina Ward as Verity Montand Tony Thawnton as Lowery
