Abstract: A releasable locking apparatus for securing a closure member to a frame includes a catch plate rigidly secured to the frame, the plate defining a catch. A locking device is pivotally secured to the closure member with the locking means defining an aperture which cooperates with the catch. The arrangement is such that in use of the apparatus, the locking device moves from a first pivotal disposition in which the catch and the aperture are spaced relative to each other to permit movement relative to the frame. The locking means moves to a second disposition in which the catch and the aperture cooperate together so that the locking means rides upon the plate. The locking device moves to a third disposition in which the catch is latchingly disposed within the aperture for securing the closure member to the frame. A backing plate is rigidly secured to the locking device for pivotal movement therewith. The arrangement is such that the closure member is disposed between the backing plate and the locking device.