Seven Days to Noon (1950)

Synopsis
Barry Jones stars as an idealistic British professor working on atomic research. Upset by the apocalyptic ramifications of his work, Jones constructs his own bomb and threatens to blow up London within one week. His terms: Stop the atomic research or suffer the consequences. As London is evacuated, the authorities close in on Jones, using a rather sophisticated form of psychological warfare to trap the unhinged scientist. Seven Days to Noon manages to sustain its suspense and realism the most part, but is slightly undermined by grainy stock footage of London's children being evacuated during World War II. ~ Hal Erickson, All Movie Guide