earlier Anderson productions. It was originally transmitted on the ITV regional franchises ATV, Granada and Southern, airing on Sundays at the regular time of 5.30 p.m. ATV and Southern showed re-runs until 1972 and Granada until 1975. Since then, the series has never been repeated in the UK. Critical response Critical reception of The Secret Service has been predominantly negative. Gerry Anderson, however, said that it was his favourite of all the series that he had produced. Leo Eaton, who directed four episodes, described The Secret Service as "just a bit weird" and questioned the effectiveness of Unwin's humour. Production supervisor Desmond Saunders called it "strange", elaborating: "I suppose it was the gobbledygook and the mixture of live action with puppets. It never seemed to me to be a very good idea." Simon Wickes of the website TVCentury21.com suggests that the series was made primarily to bridge the gap between the Andersons' puppet productions and their later efforts in live action. Kif Bowden-Smith of the Transdiffusion website describes the mixing of puppetry and live action as "an experimental format for the following live-action series". Simon Archer and Marcus Hearn, authors of What Made Thunderbirds Go! The Authorised Biography of Gerry Anderson (2002), write that The Secret Service differs from earlier Anderson series by being less "American-orientated" and featuring fewer action sequences. They regard it as the "most eccentric" of all the Supermarionation productions up to 1969, and the hybrid format as the "natural conclusion" of the filming technique. They especially commend the characterisation of Mrs Appleby, whose ignorance of Unwin and Harding's true occupations adds to the humour: for example, when Unwin speaks into his hearing aid, she deduces that he is simply muttering to himself, not knowing that the device is actually a transceiver for communicating with Harding. Archer and Hearn also praise the episodes "A Question of Miracles", which sees the miniaturised Harding dwarfed by the contents of a picnic basket, and "Last Train to Bufflers Halt", whose plot concerns a runaway freight train. Stephen La Rivière, author of Filmed in Supermarionation: A History of the Future, favours the episode "More Haste Less Speed": describing the series finale as "wonderfully quirky", he considers the plot about a money-forging scheme to be reminiscent of the "gentler, earlier days of Supercar" and lauds voice actor Keith Alexander for his impression of the elderly Lady Hazlewell. Nevertheless, in his overall assessment