A permanent magnet machine is provided comprising a stator and a rotor, the rotor being adapted to rotate relative to the stator, the rotor comprising a plurality of permanent magnets separated in the circumferential direction from each other by axially extending rotor pole pieces for concentrating the magnetic flux from the permanent magnets, the stator having a structure that defines axial limits of an air gap between the stator and the rotor for communicating magnetic flux between the stator and the rotor, wherein that at least some of the permanent magnets extend axially outside the axial limits of the air gap as defined by the stator structure.