A method of allocating communications resources in a radio communications system comprising a first subsystem (1) and a second subsystem (2) using different radio access techniques and adapted to communicate with radio terminals (3). The method comprises the following steps: determining an indication about the occupancy of the communications resources of said first and/or said second subsystem, and when a call is to be set up for a radio terminal, allocating a communications resource of the first or second subsystem to the call taking account of the indication so determined.