A valve assembly for controlling fluid flow in a throughbore of a wellbore conduit of an oil, gas or water well, the assembly comprising:- a body having an axis and being in fluid communication with the wellbore conduit, and at least one valve comprising a valve member disposed in a valve housing in the body, wherein the valve housing is adapted to move axially within the body, and including a displacement mechanism adapted to urge the valve housing axially within the body, wherein the valve member is adapted to be actuated between an open configuration and a closed configuration by axial movement of the valve housing within the body, wherein the valve is adapted to be opened by a pressure differential, arising from flow of fluid in the throughbore in an uphole to downhole direction, acting across the valve, wherein the displacement mechanism is configured to urge the valve member into the closed configuration; wherein the valve assembly includes a valve control member adapted to control axial movement of the valve housing in the body; characterised by the valve assembly incorporating a radial offset between a point of contact between the valve member and the valve control member, and a pivot axis of the valve member, whereby inter-engaging portions of the valve control member and the valve member are radially spaced from the pivot axis of the valve member, such that when the valve member is moving from the open configuration to the closed configuration the valve member abuts against the valve control member in order to urge the valve member in rotation around the pivot axis as the housing slides axially relative to the valve control member. a body having an axis and being in fluid communication with the wellbore conduit, and at least one valve comprising a valve member disposed in a valve housing in the body, wherein the valve housing is adapted to move axially within the body, and including a displacement mechanism adapted to urge the valve housing axially within the body, wherein the valve member is adapted to be actuated between an open configuration and a closed configuration by axial movement of the valve housing within the body, wherein the valve is adapted to be opened by a pressure differential, arising from flow of fluid in the throughbore in an uphole to downhole direction, acting across the valve, wherein the displacement mechanism is configured to urge the valve member into the closed configuration; wherein the valve assembly includes a valve control member adapted to control axial movement of the valve housing in the body; characterised by the valve assembly incorporating a radial offset between a point of contact between the valve member and the valve control member, and a pivot axis of the valve member, whereby inter-engaging portions of the valve control member and the valve member are radially spaced from the pivot axis of the valve member, such that when the valve member is moving from the open configuration to the closed configuration the valve member abuts against the valve control member in order to urge the valve member in rotation around the pivot axis as the housing slides axially relative to the valve control member.