Appeasement

Although Hitler offended the Treaty of Versailles in several ways, the Western powers - and especially Great Britain - did not interfere for a long time. This kind of policy is called "Appeasement". Great Britain was in a deep economic crisis at that time and therefore, they wanted to avoid another war. So, they made concessions to Hitler: they tolerated Hitler's invasion of the Rhineland, his nuclear armament and initiating the compulsory military service (which was all against the Treaty of Versailles).