Operation Sea Lion

After the fall of France in June 1940, Nazi Germany began planning an invasion of Britain under the codename Operation Sea Lion. The plan required German forces to cross the English Channel while the Luftwaffe secured sufficient control of the air and naval preparations assembled transport barges and other shipping in occupied continental ports.

British planners treated the possibility of invasion as a serious threat and strengthened coastal defence, intelligence assessment and counter-sabotage measures. German inability to defeat the Royal Air Force and the wider military risks of a Channel crossing caused the operation to be postponed and ultimately abandoned.

Alex Gerlis’s The Second Traitor is set against the invasion scare of 1940 and uses Sea Lion as the historical framework for a fictional investigation into Nazi sympathisers and Soviet double agents inside Britain.