Abstract: An improved high security locking apparatus is provided by combining an electromagnetic locking apparatus of the type which includes a lock portion and a removable key portion, the key portion providing a determined unlocking combination signal, the lock portion providing an immediate unlocking function in response to the presentation of the determined unlocking combination signal from the key portion while placed within a determined surface location of the lock portion, with an interlocked time delay circuit which provides silent, time delayed activation of the unlocking function in response to the simultaneous presence of the determined unlocking combination signal with the placement of the key portion within the determined surface location, and which inhibits the unlocking function for all other conditions.