A control system for optimising emergency multi-storey building stairwell evacuation, the system includes an occupant tracking subsystem configured to monitor the locations of building occupants within a building as the occupants move between floors of the building so as to be able to continuously calculate the number of occupants on each floor of the building at any time, such that, during an emergency. The control system is configured and able to, using an access door controller subsystem: control the closing of a plurality of access doors of a stairwell； and control the successive opening of certain access doors of certain floors of the stairwell in accordance with an evacuation plan. Wherein the evacuation plan is dynamically configured in accordance with the calculated number of occupants on each floor of the building.
