Described is a brush seal for sealing between a first component and a second component which relatively rotate during normal use, comprising: an annular housing which is attached to a first component in use; a plurality of bristles each having a fixed end attached to the housing and a free end, wherein the free ends of at least some of the plurality of bristles contact the second component during normal use to provide a sealing surface, wherein the sealing surface includes a plurality of discontinuities around the circumference of the brush seal for providing hydrodynamic lifting force in use.