Abstract: A secure sliding closure having a modular frame and one or more sliding door is described. The modular frame defines at least one secure cavity and a portal and comprises a main frame and at least one door frame. The main frame comprises at least one frame upright spaced apart from at least one portal upright and a respective at least one top plate extending between the at least one frame upright and the at least one portal upright. The at least one door frame comprising a locking side upright spaced apart from a secure cavity upright and a door frame top plate. The modular frame defines at least one secure cavity and defines a portal. The one or more sliding door comprises a sliding leaf and a sliding leaf covering, the covering comprising one or more sliding door security panel.