A protective shelter that provides protection within a war zone and which can be readily assembled in a quick, secure and reliable manner. The shelter is formed of opposite outer walls and a roof structure extending therebetween, wherein the roof structure comprises a plurality of tray members supported by beam supports and in which the plurality of tray members is arranged to receive earth, sand or aggregate material so as to provide a first layer of protection via the roof structure. The tray members can be supported by beams serving to define a shallow arch across the shelter such that the internal height of the shelter centrally, and away from the opposite walls, is greater than the height of the said walls.