A Fuel cell system

A fuel cell system (100) comprises a fuel cell (102) having an anode inlet port (104) and a cathode fluid communication port (108) and an anode pressure regulator (112). The anode pressure regulator (112) comprises a cathode chamber (114) with a cathode chamber inlet port (116); an anode chamber (118) with an anode chamber outlet port (120) and an anode chamber inlet port (122). A diaphragm (124) is between the cathode chamber (114) and the anode chamber (118) and a variable restriction element (126) is configured to control the flow of fluid into the anode chamber (118) through the anode chamber inlet port (122) in accordance with the position of the diaphragm (124). The cathode chamber inlet port (116) is in fluid communication with the cathode fluid communication port (108) of the fuel cell (102). The anode chamber outlet port (120) is in fluid communication with the anode inlet port (104) of the fuel cell (102). The anode chamber inlet port (122) is configured to be in fluid communication with a fuel source for the fuel cell. Advantageously the pressure differential across a membrane in the fuel cell can be controlled in order to reduce the likelihood of damage to the fuel cell.