In the final few months of the Second World War, Hitler's revolutionary V1 and V2 missiles terrorised southern England. In London alone, 25,000 homes were levelled and 8,000 people killed as this country became the first to suffer major ballistic missile bombardment from beyond its borders. In remarkable film footage, screened for the first time, of the weapons in various stages of planning and production, Nazi archives reveal how Germany established a technological advantage that could have changed the outcome of the Second World War.