How successful was Germany at reading Royal Navy codes during World War II?
Short answerIt had some successes, but frequent British code changes and weaker intelligence access prevented sustained exploitation.
NotesRoyal Navy communications are not described as unbreakable. Their defence depended on changing systems regularly once compromise became possible. German analysts could make progress, but their window of usefulness closed when the British replaced a code. Germany also lacked an intelligence operation inside Britain comparable to the access Britain developed against Germany.