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 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 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. <EOS>