may include for example fluid pressure from control lines to the surface mechanical actuation components or remote electronic actuation components examples of suitable valves are ball valves flapper valves and sleeve valves u201d fig2 illustrates a schematic representation of an actuating apparatus 12 according an embodiment of the present invention the actuating apparatus 12 provides a secondary actuator operable to close a downhole valve 10 see fig1 that has failed to close under primary actuation such as by applying fluid pressure via control lines from surface the actuating apparatus 12 according to an embodiment of the present invention comprises a tubular body 30 which includes an axial bore 32 between an inlet end 34 and an outlet end 36 the inlet 34 and the outlet 36 each comprise a threaded connection 38 40 for attachment to the production tubing 22 see fig1 of a downhole assembly the actuating apparatus 12 also comprises an operating sleeve 42 which is movable relative to the body 30 as described further below with reference to fig3 the body 30 and the sleeve 42 are assembled coaxially such that an annular reservoir 44 is defined between them the annular reservoir 44 contains hydraulic fluid which is compressed and displaced upon displacement of the sleeve 42 due to the action of removal of the stinger not illustrated the body 30 includes.