A comic strip featuring the characters of Lady Penelope and Parker, set prior to their joining International Rescue, debuted in the first weekly issues of AP Films Publishing's children's title TV Century 21 in early 1965, several months prior to the first broadcast of "Trapped in the Sky" [REF].
A Thunderbirds Annual was published by Century 21 Publishing from 1966 to 1968, and a Lady Penelope version until 1969 [REF].