 The episode to feature the largest cast of characters (in speaking  roles) seen in any single "Thunderbirds" episode or either of the  feature films was "Alias Mr. Hackenbacker", with 20 voices provided  by all of the cast members from the second season  (Jeremy Wilkin (qv) had replaced David Holliday (I) (qv) as the  voice of Virgil at this time), featuring Paul Maxwell (I) (qv) as  Capt. Ashton, although he was not credited in the end titles.