A valve assembly comprising: a fluid flow passage to permit a flow of a fluid through the valve assembly; a valve seat; and an actuator assembly comprising: an actuator body in a fixed position relative to the valve seat; a valve member moveable relative to the valve seat between a first position in which the valve member is at least partially engaged with the valve seat to at least partially block the fluid flow passage, and a second position in which the valve member is remote from the valve seat, wherein the valve member is moveable relative to the actuator body and extends around the actuator body such that the actuator body is disposed within the valve member, and a bellows received within the valve member, and attached to the valve member and to the actuator body, the bellows comprising an interior surface and an exterior surface opposite to the interior surface; wherein the interior surface of the bellows, the actuator body, and the valve member define a control chamber therebetween, wherein the exterior surface of the bellows and the valve member define an outer volume therebetween such that the outer volume is around the control chamber, characterised in that the valve member comprises at least one orifice extending therethrough and in that the at least one orifice fluidly communicates the control chamber with the outer volume. a fluid flow passage to permit a flow of a fluid through the valve assembly; a valve seat; and an actuator assembly comprising: an actuator body in a fixed position relative to the valve seat; a valve member moveable relative to the valve seat between a first position in which the valve member is at least partially engaged with the valve seat to at least partially block the fluid flow passage, and a second position in which the valve member is remote from the valve seat, wherein the valve member is moveable relative to the actuator body and extends around the actuator body such that the actuator body is disposed within the valve member, and a bellows received within the valve member, and attached to the valve member and to the actuator body, the bellows comprising an interior surface and an exterior surface opposite to the interior surface; wherein the interior surface of the bellows, the actuator body, and the valve member define a control chamber therebetween, wherein the exterior surface of the bellows and the valve member define an outer volume therebetween such that the outer volume is around the control chamber, characterised in that the valve member comprises at least one orifice extending therethrough and in that the at least one orifice fluidly communicates the control chamber with the outer volume. an actuator body in a fixed position relative to the valve seat; a valve member moveable relative to the valve seat between a first position in which the valve member is at least partially engaged with the valve seat to at least partially block the fluid flow passage, and a second position in which the valve member is remote from the valve seat, wherein the valve member is moveable relative to the actuator body and extends around the actuator body such that the actuator body is disposed within the valve member, and a bellows received within the valve member, and attached to the valve member and to the actuator body, the bellows comprising an interior surface and an exterior surface opposite to the interior surface; wherein the interior surface of the bellows, the actuator body, and the valve member define a control chamber therebetween, wherein the exterior surface of the bellows and the valve member define an outer volume therebetween such that the outer volume is around the control chamber, characterised in that the valve member comprises at least one orifice extending therethrough and in that the at least one orifice fluidly communicates the control chamber with the outer volume.