This book delves into the dark and haunting cinematic and televisual portrayals of the sea in British culture, revealing the hidden narratives that challenge the nation's cherished myths of isolation and exceptionalism. Through a compelling exploration of horror and gothic genres, it uncovers the repressed voices and forgotten histories that lie beneath Britain's maritime identity. The chapters investigate key themes such as the myth of the 'island nation,' the duality of maritime legends, and the cultural significance of marine horror in film and television. By examining works from Joseph Conrad to M.R. James, this book highlights how these narratives reflect internal debates and contradictions within British society. Readers will discover how media cultures construct and challenge collective identity, offering a fresh perspective on Britain's relationship with its maritime past. Aimed at academics in film, television, and cultural studies, as well as general readers intrigued by British history and horror, this book is a must-read for anyone interested in the intersection of media, mythology, and national identity. It speaks to scholars of Gothic literature, Blue Humanities enthusiasts, and those curious about ecological representations in screen media. In an era of heightened scrutiny on British values, this work offers a timely exploration of the stories we tell—and those we choose to forget.