An apparatus for use in charged particle therapy, comprising: a bending device configured to receive beams of charged particles and; a gantry for focussing beams of charged particles having differing momentum to charge ratios to a substantially common point, the gantry comprising: at least one toroidal magnet having a central bore, a primary axis of the toroidal magnet extending along the central bore, wherein the bending device is configured to direct beams of charged particles towards the gantry dependent on the momentum to charge ratios of the beams; wherein the toroidal magnet is configured to receive the beams of charged particles at different radial locations dependent on the momentum to charge ratio of the beam; wherein the toroidal magnet comprises a plurality of discrete, substantially planar coils spaced apart and extending radially from the primary axis and configured to produce a magnetic field such that, in use, a first beam of charged particles having a component of motion along the primary axis and entering the gantry at a first radial location, is directed towards a first point on the primary axis, and; a second beam of charged particles having a different momentum to charge ratio to the first beam, and having a component of motion along the primary axis and entering the gantry at a second radial location, is directed towards said first point on the primary axis, and wherein; the planar coils are configured to produce a magnetic field that is periodically symmetric about the primary axis, and; the gantry is substantially stationary in use, and wherein; in use, a subject is positioned within the central bore of the at least one toroidal magnet. a bending device configured to receive beams of charged particles and; a gantry for focussing beams of charged particles having differing momentum to charge ratios to a substantially common point, the gantry comprising: at least one toroidal magnet having a central bore, a primary axis of the toroidal magnet extending along the central bore, wherein the bending device is configured to direct beams of charged particles towards the gantry dependent on the momentum to charge ratios of the beams; wherein at least one toroidal magnet having a central bore, a primary axis of the toroidal magnet extending along the central bore, wherein the bending device is configured to direct beams of charged particles towards the gantry dependent on the momentum to charge ratios of the beams; wherein the toroidal magnet is configured to receive the beams of charged particles at different radial locations dependent on the momentum to charge ratio of the beam; wherein the toroidal magnet comprises a plurality of discrete, substantially planar coils spaced apart and extending radially from the primary axis and configured to produce a magnetic field such that, in use, a first beam of charged particles having a component of motion along the primary axis and entering the gantry at a first radial location, is directed towards a first point on the primary axis, and; a second beam of charged particles having a different momentum to charge ratio to the first beam, and having a component of motion along the primary axis and entering the gantry at a second radial location, is directed towards said first point on the primary axis, and wherein; the planar coils are configured to produce a magnetic field that is periodically symmetric about the primary axis, and; the gantry is substantially stationary in use, and wherein; in use, a subject is positioned within the central bore of the at least one toroidal magnet.