An aircraft landing gear assembly comprising: a main strut arranged to be movably coupled to an aircraft so as to be movable between a deployed condition for take-off and landing, and a stowed condition for flight; a support linkage coupled at a first anchor point to the main strut and having a second anchor point arranged to be coupled to the aircraft, the support linkage having a locked condition in which it is arranged to inhibit movement of the main strut from the deployed condition in one or more planes of movement and an unlocked condition in which it permits the main strut to move from the deployed condition to the retracted condition, the support linkage comprising a split tube spring having a longitudinal axis and a longitudinal slot, the split tube spring being biased to assume a tubular condition in which it can react axial loading thereof, the support linkage being in the locked condition when the split tube spring is in the tubular condition and being in the unlocked condition when the split tube spring is in a folded condition; and an actuator operable to radially enlarge a region of the split tube spring for the split tube spring to fold at the radially enlarged region to assume the folded condition, the actuator comprising a flexible vessel arranged to be coupled to a source of pressurising fluid via a fluid port, the flexible vessel comprising a flexible first portion which extends transverse with respect to the longitudinal axis of the split tube spring such that when pressuring fluid is introduced into the flexible vessel the flexible portion straightens to radially enlarge the region of the split tube spring to permit the split tube spring to assume the folded condition characterised in that the flexible vessel is T shaped and comprises the first portion that extends across the split tube spring at an angle of between 45° and 135°, and further comprises a supply conduit which extends along the split tube spring to fluidly couple the flexible first portion to the port for introducing the pressurising fluid into the flexible vessel. a main strut arranged to be movably coupled to an aircraft so as to be movable between a deployed condition for take-off and landing, and a stowed condition for flight; a support linkage coupled at a first anchor point to the main strut and having a second anchor point arranged to be coupled to the aircraft, the support linkage having a locked condition in which it is arranged to inhibit movement of the main strut from the deployed condition in one or more planes of movement and an unlocked condition in which it permits the main strut to move from the deployed condition to the retracted condition, the support linkage comprising a split tube spring having a longitudinal axis and a longitudinal slot, the split tube spring being biased to assume a tubular condition in which it can react axial loading thereof, the support linkage being in the locked condition when the split tube spring is in the tubular condition and being in the unlocked condition when the split tube spring is in a folded condition; and an actuator operable to radially enlarge a region of the split tube spring for the split tube spring to fold at the radially enlarged region to assume the folded condition, the actuator comprising a flexible vessel arranged to be coupled to a source of pressurising fluid via a fluid port, the flexible vessel comprising a flexible first portion which extends transverse with respect to the longitudinal axis of the split tube spring such that when pressuring fluid is introduced into the flexible vessel the flexible portion straightens to radially enlarge the region of the split tube spring to permit the split tube spring to assume the folded condition characterised in that the flexible vessel is T shaped and comprises the first portion that extends across the split tube spring at an angle of between 45° and 135°, and further comprises a supply conduit which extends along the split tube spring to fluidly couple the flexible first portion to the port for introducing the pressurising fluid into the flexible vessel.