on Thursday 4 January 1968 on Scottish Television, on Sunday 7 January on ATV London, whose broadcasts were also taken up by Southern Television, Westward Television and Tyne-Tees; on Friday 12 January on Border Television and on Friday 19 January on Granada Television in the North West. The aggregate viewing figures for the ITV regions that debuted the season in 1967 have been estimated at 7.3 million. In Northern Ireland, the episode did not debut until Saturday 23 March 1968, and in Wales, the episode was not broadcast until Wednesday 25 March 1970. Notes This is one of the few Prisoner episodes to begin with a pre-credits teaser sequence (as well as the recap which opens "Fall Out" and the unusual structure of "Living in Harmony"). It shows several men, including one who will be identified later in the episode as the former superior of Number 6, trying to find clues to the whereabouts of Professor Seltzman in a group of seemingly innocuous photographic slides of Seltzman on holiday. According to The Prisoner by Robert Fairclough, had the serial been renewed for a second series, the format would have followed that presented in this episode, with Number 6 being sent out on missions on behalf of The Village. Also missing from the episode is the usual Number Two introductory sequence that follows the opening titles. Instead, Number Six – having woken up – looks out of his window to see the helicopter carrying The Colonel landing. The incidental music is also different in this sequence. McGoohan appears only at the very beginning and the very end of the episode, the role of Number 6 (after the mind transfer) being played the rest of the time by Nigel Stock. He also appears in voiceover as Six's internal monologue, and in stock footage from previous episodes. Modern remastered editions also clearly show that the driving sequences in London are actually stock footage of McGoohan. The episode was so formatted in order to allow McGoohan to take a leave of absence from the series to film his role in the motion picture Ice Station Zebra. It has been theorised that calling Stock's character "The Colonel" was a misinterpretation of McGoohan's instructions in his absence. In the two other episodes when The Prisoner manages/seems to return to London and contacts his former superiors ("The Chimes of Big Ben" and "Many Happy Returns"), the man