While there has been a growing acknowledgement of the existence of earlier examples of television science fiction, the typical history of the genre still privileges Nigel Kneale’s The Quatermass Experiment (1953) as foundational. This was a significant production, and an effective piece of television drama, but it was not the first piece of British television science fiction, nor the first British television science fiction serial, nor even the first such serial to have a sequel. This paper will draw upon the early history of British television science fiction, particularly focusing on comparisons between the Quatermass serials and the first British TV SF serial, Stranger From Space (1951-1953), in considering the factors that lead to the ‘forgetting’ of particular productions, including marketing, adaptation and target audience. Stranger From Space was produced as ten-minute episodes within a children’s magazine programme, and written by Hazel Adair and Ronald Marriott. It was thus not associated with ‘serious’ programming for an adult audience and, while a novelisation was published, the serial was not recorded or adapted for the cinema, meaning it had very little afterlife, unlike The Quatermass Experiment. Despite Adair’s subsequent long career as a television writer and producer, Stranger From Space lacked a capable self-promoter and mythologiser like Nigel Kneale, whose presentations of British television before him have become important to television history, despite editing out key material, including his own pre-Quatermass adaptations of science fiction material. This paper will thus also engage with the wider issues of the construction of history.