In 1940 Britain faced its biggest threat since the Spanish Armada. Hitler's invasion plans were in full swing and Britain had to quickly assemble a secret resistance force. This compelling study reveals the intentions of both side, from Hitler's strategies for Operation Sea Lion and subsequent occupation, to Britain's secret plans for resistance. German decrees show that the occupation would have been severe, with mass deportation for all able-bodied men as well as widespread arrests, as revealed in the notorious Gestapo Arrest List. In telling this story Lampe relates one of World War II's best kept secrets and offers insight into what would have been a brutal future.