We lived scant miles from the Broadmoor Asylum for the Criminally Insane (as it was called in those days).  From time to time the siren would go, heralding the escape of a patient.  My sister's girl's school in Wokingham was promptly evacuated and all the girls were escorted home.  Nobody cared about us boys.  The bell rang, we got on the steam train and got ourselves home.

Also, in those days there was no "all clear".  Escapees were usually caught within a few minutes, still on asylum grounds.  But the public never got to know about that until the weekly local newspaper announced it several days later.