the lever tumbler lock was greatly improved by jeremiah chubb in  a burglary in portsmouth dockyard prompted the british government to announce a competition to produce a lock that could be opened only with its own key chubb developed the chubb detector lock which incorporated an integral security feature that could frustrate unauthorised access attempts and would indicate to the locks owner if it had been interfered with chubb was awarded £ after a trained lock-picker failed to break the lock after  months