Abstract: A reservation system for managing access to access controlled locations by issuing an access code that is valid at a particular lock for a particular time. The reservation system includes a standalone lock that has a processor, clock and memory. The processor of the lock checks an access code entered at a given time against the access codes stored in the memory to determine if they are valid for the given time provided by the clock. The reservation system also include a management module that receives a booking and issues an access code. A user interface is provided for a user to interact with the functions of the management module. The invention also includes a method of booking an access controlled location, a method of monitoring an access controlled location, an a standalone lock for an access controlled location.