A flux switching electrical machine for converting electrical energy into mechanical energy and/or mechanical energy into electrical energy, the machine comprising: a stator; a rotor; and a control means; the stator comprising: field slots (202,204,206,208) carrying a field winding (104,330) for the creation of field flux; and an armature assembly comprising one armature winding positioned in armature slots (201,203,205,207) between stator teeth, the stator teeth extending radially towards an air-gap between stator and rotor; wherein: a width of a gap across the armature slot openings at the air-gap surface is different to the width of a gap across the field slot openings at the air-gap surface; the rotor has teeth extending radially towards the air-gap between rotor and stator; and the control means is configured to control an inverter to provide excitation signals to the electrical machine, the control means being configured to create an imbalance between the excitation levels of current flowing in the armature winding and field winding; characterised in that each of at least two of the rotor teeth comprises a relatively high permeability section comprising a material having a magnetic permeability greater than that of air, and a relatively low permeability section comprising a material having a magnetic permeability less than or equal to that of air, so as to have different permeabilities parallel to and perpendicular to the air-gap, such that stator flux entering the rotor teeth from the air-gap sees a relatively high reluctance in paths parallel to the air-gap and a relatively low reluctance path in paths radial to the air-gap; and in that the control means is configured to provide an excitation level of current in the field winding (104,330) substantially higher than the excitation level of current in the armature winding for a period of time sufficient to allow the rotor to turn to a position of maximum field flux for the given excitation. a stator; a rotor; and a control means; the stator comprising: field slots (202,204,206,208) carrying a field winding (104,330) for the creation of field flux; and an armature assembly comprising one armature winding positioned in armature slots (201,203,205,207) between stator teeth, the stator teeth extending radially towards an air-gap between stator and rotor; field slots (202,204,206,208) carrying a field winding (104,330) for the creation of field flux; and an armature assembly comprising one armature winding positioned in armature slots (201,203,205,207) between stator teeth, the stator teeth extending radially towards an air-gap between stator and rotor; wherein: a width of a gap across the armature slot openings at the air-gap surface is different to the width of a gap across the field slot openings at the air-gap surface; the rotor has teeth extending radially towards the air-gap between rotor and stator; and the control means is configured to control an inverter to provide excitation signals to the electrical machine, the control means being configured to create an imbalance between the excitation levels of current flowing in the armature winding and field winding; a width of a gap across the armature slot openings at the air-gap surface is different to the width of a gap across the field slot openings at the air-gap surface; the rotor has teeth extending radially towards the air-gap between rotor and stator; and the control means is configured to control an inverter to provide excitation signals to the electrical machine, the control means being configured to create an imbalance between the excitation levels of current flowing in the armature winding and field winding; characterised in that each of at least two of the rotor teeth comprises a relatively high permeability section comprising a material having a magnetic permeability greater than that of air, and a relatively low permeability section comprising a material having a magnetic permeability less than or equal to that of air, so as to have different permeabilities parallel to and perpendicular to the air-gap, such that stator flux entering the rotor teeth from the air-gap sees a relatively high reluctance in paths parallel to the air-gap and a relatively low reluctance path in paths radial to the air-gap; and in that the control means is configured to provide an excitation level of current in the field winding (104,330) substantially higher than the excitation level of current in the armature winding for a period of time sufficient to allow the rotor to turn to a position of maximum field flux for the given excitation.