 The feature @-@ length film sequels Thunderbirds Are Go and Thunderbird 6 were released in 1966 and 1968 . The first was <unk> by Lew Grade before the TV series had started its broadcast run . Written and produced by the Andersons and directed by David Lane , both films were distributed by United Artists . Neither was a critical or commercial success , and Century 21 Cinema 's plans for further sequels were abandoned . 
