A linear sliding hydraulic valve with emergency actuation, comprising: • a valve body including at least one inlet and at least one outlet (401, 401'); • a sliding member inside the valve body to allow or prevent the passage of a fluid operating in inlet and outlet (401, 401'); • a first and second primary actuators (200, 200') arranged at axially opposite sides of said valve body for the actuation under standard operative conditions of said sliding member in said valve body; • a secondary actuator for a secondary actuation of said sliding member in said valve body, wherein said secondary actuator is interposed between said valve body and said first primary actuator or said secondary actuator, and wherein said secondary actuator comprises: • a secondary actuator body; • an axial member slidably driven in said secondary actuator body and interposed between the sliding member and the primary actuator, to transmit the action exerted by said primary actuator to the sliding member; and • a mechanical actuation configured to be accessible from the outside of the secondary actuator body, to translate said axial member from and to an actuating position of the sliding member independently of the actuation of the primary actuator, wherein said mechanical actuation comprises a shaped movable body and a motion conversion mechanism to convert a motion of said shaped movable body into a translational motion of the axial member • characterized in that the motion of said shaped movable body converted by said motion conversion mechanism comprises a rotational movement of said shaped movable body about an axis oriented according to a substantially radial direction with respect to said axial member or a translational movement along said axis oriented according to a substantially radial direction with respect to said axial member. • a valve body including at least one inlet and at least one outlet (401, 401'); • a sliding member inside the valve body to allow or prevent the passage of a fluid operating in inlet and outlet (401, 401'); • a first and second primary actuators (200, 200') arranged at axially opposite sides of said valve body for the actuation under standard operative conditions of said sliding member in said valve body; • a secondary actuator for a secondary actuation of said sliding member in said valve body, • a secondary actuator body; • an axial member slidably driven in said secondary actuator body and interposed between the sliding member and the primary actuator, to transmit the action exerted by said primary actuator to the sliding member; and • a mechanical actuation configured to be accessible from the outside of the secondary actuator body, to translate said axial member from and to an actuating position of the sliding member independently of the actuation of the primary actuator, wherein said mechanical actuation comprises a shaped movable body and a motion conversion mechanism to convert a motion of said shaped movable body into a translational motion of the axial member • characterized in that the motion of said shaped movable body converted by said motion conversion mechanism comprises a rotational movement of said shaped movable body about an axis oriented according to a substantially radial direction with respect to said axial member or a translational movement along said axis oriented according to a substantially radial direction with respect to said axial member.