The project investigates the 1950s Quatermass films (The Quatermass Experiment , Quatermass II  produced by Hammer, within their production contexts. Despite the assertion that Hammer horror productions were 'initiated by the enormous commercial success' (Hutchings, 1993: 25) of the Quatermass films, they have not been afforded the critical recognition they merit. Reassessment of the cultural importance of the Quatermass phenomenon is needed. This study addresses critical discourses on British film and the fantastic. As part of addressing the neglect within current scholarship of the Quatermass films, the privileging of the realist aesthetic within film criticism is discussed as part of the context for this neglect. While there has been increased interest in horror and science fiction in more recent writings and hitherto neglected films have been re-discovered, the Quatermass films have not enjoyed comparable critical space. My study goes on to illustrate this gap in the literature on Quatermass, which this study redresses. An underlying theme throughout the thesis is hybridity. Moving from discussion of how the hybrid text might cause difficulties for critical discourse that seeks finite definitions of film categories and an emphasis on realism within the film text, I address the hybrid within the production contexts and thematic content of the Quatermass films. How does the British/American co-production inform the films and contemporaneous responses to them? How is the hybrid configured within the text; as something troubling, to be feared, or is the response more complex with the potential for more positive readings?Discussion of the hybrid is combined with the fantastic and the uncanny, the emphasis being on the subversive potential of these modes and how they have potential to de-stabilise the "real", and, by extension, dominant ideologies. How might hybridity, the fantastic and the uncanny problematise concepts of identity and "nation"? Concepts of "nation" and "national identity" will be emphasised as contested categories, contingent and inherently hybrid. How are these questions of identity mapped out within and through the Quatermass films and beyond?