Improved intrusion detection system and method

An intrusion detection system which operates in a restricted mode 122 for restricting access to areas. Individuals are assigned permissions by an administrator which allows access or disallows access to specific regions of a building. The restricted regions are specific to each individual 105. The system further has intrusion detection sensors 120 such as motion detectors and window or door contacts for ascertaining to presence of an individual 110. If the individual is identified as an authorised person, no alarm will trigger. If an unauthorised person is detected an alarm is triggered which can be an image or text notification sent to a mobile device 132 carried by an administrator. The system allows remote operation of intrusion elements 152, such as locks on windows and doors. The system may further operate in different modes including a fully armed mode 180, a perimeter armed mode 170 and a disarmed mode 160. The identity of an individual is determined from entering an access code upon entry to the premises or an RFID device carried by the individual.