Tubing or annulus pressure operated borehole barrier valve

An actuation assembly for a tubular string mounted barrier valve, comprising:

• a housing;
• a double acting piston within the housing operably connected to a valve member such that movement of said piston n a first direction opens the barrier valve and movement of said piston n a second direction closes the barrier valve;
• opposed compartments defined within the housing on opposed sides of the double acting piston, the opposed compartments comprising a first compartment and a second compartment;
• a hydraulically operated valved manifold comprising an inlet pressure source from an annular space about said tubing string, said manifold selectively directing said inlet pressure source into said first compartment to flow fluid from the second compartment to a lower pressure location as the double acting piston is moved in a first direction;
• and
• said manifold further selectively directing said inlet pressure source into said second compartment via actuation of at least one valve within the valved manifold to flow fluid from the first compartment to the lower pressure location as the double acting piston is moved in a second direction;
• wherein said valved manifold comprises a pair of valves selectively operated by said inlet pressure source which are repositioned in tandem between first and second configurations, wherein in the first configuration the valves open a first flow path from the inlet pressure source to the first compartment while isolating the first flow path from the lower pressure location and in the second configuration the valves open a second flow path from the inlet pressure source to the second compartment while isolating the second compartment from the lower pressure location.