Method of determining a location of a mobile device and method of managing a list for use in such a method

A mobile device arranged to be part of a first communication network and a second communication network, the mobile device comprising:

• a receiver for receiving data from one or more communication units in the first communication network or the second communication network;
• a memory for storing a list of records of communication units located within a predetermined geographical area;
• and
• a processor for processing data received via said receiver and processing the list stored in said memory and further configured to:
• obtain the list of records of communication units within the first or second communication network that are located within a predetermined geographical area, the communication unit records comprising information representative of the identity of each respective communication units, information representative of a position of each respective communication units, and a reliability indication of each respective communication unit;
• detect communication units within the first and second communication network;
• and
• determine the location of the mobile device based on the information representative of the position of selected detected communication units, wherein such selection is based on the information representative of the position, the reliability indication, and an accuracy indication of the detected communication units, wherein the selection is further based on a distance between positions of the detected communication units indicated by the information representative of the position of respective communication units.