Apparatus (200") for use as a motor or generator, comprising: a first part; a second part movable relative to the first part and spaced from the first part by an air gap; a plurality of spaced activatable magnet elements provided on the first part, each activatable magnet element being operative when activated by application of an electric current thereto to direct a magnetic field across the air gap towards the second part; wherein each activatable magnet element comprises: a pole piece defining an air-gap facing surface (223A, 223B), the pole piece comprising: a first limb; a second limb; and a coil-winding section positioned between the first and second limbs (224A, 224B); a permanent magnet arrangement provided between the first and second limbs (224A, 224B) of the pole piece; and an electrically conductive coil wound around the coil-winding section of the pole piece, wherein the electrically conductive coil is operative to generate a magnetic flux oriented to oppose the magnetic flux of the permanent magnet arrangement; wherein the pole piece further comprises a parallel flux path section extending in parallel to the coil-winding section and operative to allow magnetic flux from the permanent magnet arrangement to flow in parallel to the coil-winding section; and control circuitry operative to control current supply to the electrically conductive coils of the plurality of activatable magnet elements; characterised in that: in an inactive mode of operation the electrically conductive coil is de-energised and magnetic flux from the permanent magnet arrangement preferentially flows in parallel through the coil-winding section and parallel flux path section in preference to across the air gap; and in an active mode of operation the electrically conductive coil is energised to generate a magnetic flux to oppose the magnetic flux of the permanent magnet arrangement, wherein the magnetic flux generated by the coil circulates back to the coil via the parallel flux path section, and the magnetic flux from the permanent magnet arrangement preferentially flows across the air gap. a first part; a second part movable relative to the first part and spaced from the first part by an air gap; a plurality of spaced activatable magnet elements provided on the first part, each activatable magnet element being operative when activated by application of an electric current thereto to direct a magnetic field across the air gap towards the second part; wherein each activatable magnet element comprises: a pole piece defining an air-gap facing surface (223A, 223B), the pole piece comprising: a first limb; a second limb; and a coil-winding section positioned between the first and second limbs (224A, 224B); a permanent magnet arrangement provided between the first and second limbs (224A, 224B) of the pole piece; and an electrically conductive coil wound around the coil-winding section of the pole piece, wherein the electrically conductive coil is operative to generate a magnetic flux oriented to oppose the magnetic flux of the permanent magnet arrangement; a pole piece defining an air-gap facing surface (223A, 223B), the pole piece comprising: a first limb; a second limb; and a coil-winding section positioned between the first and second limbs (224A, 224B); a first limb; a second limb; and a coil-winding section positioned between the first and second limbs (224A, 224B); a permanent magnet arrangement provided between the first and second limbs (224A, 224B) of the pole piece; and an electrically conductive coil wound around the coil-winding section of the pole piece, wherein the electrically conductive coil is operative to generate a magnetic flux oriented to oppose the magnetic flux of the permanent magnet arrangement; wherein the pole piece further comprises a parallel flux path section extending in parallel to the coil-winding section and operative to allow magnetic flux from the permanent magnet arrangement to flow in parallel to the coil-winding section; and control circuitry operative to control current supply to the electrically conductive coils of the plurality of activatable magnet elements; characterised in that: in an inactive mode of operation the electrically conductive coil is de-energised and magnetic flux from the permanent magnet arrangement preferentially flows in parallel through the coil-winding section and parallel flux path section in preference to across the air gap; and in an active mode of operation the electrically conductive coil is energised to generate a magnetic flux to oppose the magnetic flux of the permanent magnet arrangement, wherein the magnetic flux generated by the coil circulates back to the coil via the parallel flux path section, and the magnetic flux from the permanent magnet arrangement preferentially flows across the air gap. in an inactive mode of operation the electrically conductive coil is de-energised and magnetic flux from the permanent magnet arrangement preferentially flows in parallel through the coil-winding section and parallel flux path section in preference to across the air gap; and in an active mode of operation the electrically conductive coil is energised to generate a magnetic flux to oppose the magnetic flux of the permanent magnet arrangement, wherein the magnetic flux generated by the coil circulates back to the coil via the parallel flux path section, and the magnetic flux from the permanent magnet arrangement preferentially flows across the air gap.