A hydraulic damper, in particular a motor vehicle suspension damper, comprising: a tube; a piston assembly disposed slidably inside the tube and attached to a piston rod led outside the tube through a sealed piston rod guide located at the end of the tube, wherein a rebound chamber filled with working liquid is defined between said piston rod guide and said piston assembly; an additional valve assembly, wherein a compression chamber filled with working liquid is defined between said piston assembly and said additional valve assembly; a slidable partition, wherein an additional compensation chamber filled with working liquid is defined between said additional valve assembly and one side of said slidable partition; a gas chamber filled with pressurised gas and defined at the other side of said slidable partition; wherein said piston assembly is provided with rebound valves and compression valves to control the flow of working liquid passing between said rebound chamber and said compression chamber, respectively, during rebound and compression stroke of the damper, and said additional valve assembly is provided with a rebound valve a and compression valve to control the flow of working liquid passing between said additional compensation chamber and said compression chamber, respectively, during rebound and compression portions of the stroking cycle of the damper, wherein it is provided with an additional chamber assembly, wherein one end of said additional chamber assembly is attached to said slidable piston assembly or to said piston rod at the compression side thereof and the other end of said additional chamber assembly is terminated with said additional valve assembly, wherein said pressurised gas chamber and said additional compensation chamber are located inside said additional chamber assembly and are separated by said slidable partition, characterised in that said additional chamber assembly is a separate subassembly of the damper independently assembled and filled with a pressurized gas. a tube; a piston assembly disposed slidably inside the tube and attached to a piston rod led outside the tube through a sealed piston rod guide located at the end of the tube, wherein a rebound chamber filled with working liquid is defined between said piston rod guide and said piston assembly; an additional valve assembly, wherein a compression chamber filled with working liquid is defined between said piston assembly and said additional valve assembly; a slidable partition, wherein an additional compensation chamber filled with working liquid is defined between said additional valve assembly and one side of said slidable partition; a gas chamber filled with pressurised gas and defined at the other side of said slidable partition; wherein said piston assembly is provided with rebound valves and compression valves to control the flow of working liquid passing between said rebound chamber and said compression chamber, respectively, during rebound and compression stroke of the damper, and said additional valve assembly is provided with a rebound valve a and compression valve to control the flow of working liquid passing between said additional compensation chamber and said compression chamber, respectively, during rebound and compression portions of the stroking cycle of the damper, wherein it is provided with an additional chamber assembly, wherein one end of said additional chamber assembly is attached to said slidable piston assembly or to said piston rod at the compression side thereof and the other end of said additional chamber assembly is terminated with said additional valve assembly, wherein said pressurised gas chamber and said additional compensation chamber are located inside said additional chamber assembly and are separated by said slidable partition,