A vehicle suspension fork comprising: a damping fluid chamber (828; 861) having a variable volume; a reservoir chamber (822; 875) in fluid communication with the damping fluid chamber (828; 861); a flow restriction (870, 871) disposed in a flow path between the damping fluid chamber (828; 861) and the reservoir chamber (822; 875); and a compressible chamber separated from the reservoir chamber (822; 875) by a flexible bladder (836; 880), said compressible chamber is filled with gas under pressure, and said flexible bladder (836; 880) communicates said gas pressure to a damping fluid in said reservoir chamber (822; 891); wherein said damping fluid chamber (828; 861) comprises a damping piston mounted on a piston shaft, wherein during compression of said suspension fork said damping piston and said piston shaft move into said damping fluid chamber (828; 861), and said flexible bladder (836; 880) enables compression of the compressible chamber to accommodate the increasing volume of the piston shaft in the damping fluid chamber (828; 861); and wherein said compressible chamber has a volume that is configured in proportion to the volume of the shaft that, at most, may enter the damping fluid chamber (828; 861) during compression; characterised in that said flow restriction comprises a movable valve outer nested within a valve inner, an annular fluid chamber formed between the movable valve outer and the valve inner, wherein the movable valve outer obstructs a plurality of boost valve orifices that provide a fluid path between the damping fluid chamber (828; 861) and the reservoir chamber (822; 875); wherein in use during a compression stroke, damping fluid acts to force the movable valve outer closer to the valve inner so as to force movable valve outer against the plurality of boost valve orifices, thereby increasing resistance to damping fluid flow through the plurality of boost valve orifices and the compressive damping force of the vehicle suspension fork. a damping fluid chamber (828; 861) having a variable volume; a reservoir chamber (822; 875) in fluid communication with the damping fluid chamber (828; 861); a flow restriction (870, 871) disposed in a flow path between the damping fluid chamber (828; 861) and the reservoir chamber (822; 875); and a compressible chamber separated from the reservoir chamber (822; 875) by a flexible bladder (836; 880), said compressible chamber is filled with gas under pressure, and said flexible bladder (836; 880) communicates said gas pressure to a damping fluid in said reservoir chamber (822; 891); wherein said damping fluid chamber (828; 861) comprises a damping piston mounted on a piston shaft, wherein during compression of said suspension fork said damping piston and said piston shaft move into said damping fluid chamber (828; 861), and said flexible bladder (836; 880) enables compression of the compressible chamber to accommodate the increasing volume of the piston shaft in the damping fluid chamber (828; 861); and wherein said compressible chamber has a volume that is configured in proportion to the volume of the shaft that, at most, may enter the damping fluid chamber (828; 861) during compression; characterised in that said flow restriction comprises a movable valve outer nested within a valve inner, an annular fluid chamber formed between the movable valve outer and the valve inner, wherein the movable valve outer obstructs a plurality of boost valve orifices that provide a fluid path between the damping fluid chamber (828; 861) and the reservoir chamber (822; 875); wherein in use during a compression stroke, damping fluid acts to force the movable valve outer closer to the valve inner so as to force movable valve outer against the plurality of boost valve orifices, thereby increasing resistance to damping fluid flow through the plurality of boost valve orifices and the compressive damping force of the vehicle suspension fork.