Sherlock Holmes and the Secret Weapon (1943)

Basil Rathbone, Nigel Bruce and Lionel Atwill star in director Roy William Neill's Second World War spy adventure. Sherlock Holmes smuggles the Swiss scientist Dr Franz Tobel from under the noses of the Gestapo and brings him to England. Tobel has invented a revolutionary bomb sight that could hand victory to whichever side has it. Tobel tells RAF Bomber Command that, to protect sight's secrets, he has split details of its manufacture and assembly between four fellow Swiss scientists. Unfortunately, Tobel is then abducted by Professor Moriarty. Luckily, Tobel had the foresight to leave a note for Holmes, in pictographic code, naming the other scientists and giving their locations. And so Holmes, Dr Watson and Inspector Lestrade set out to stop the secret weapon falling into the hands of the Nazis.