Abstract: The container includes a sheet rolled or folded into a tube of a required cross-section and a bottom cap and top cap for the tube ends, each end cap defining an endless groove corresponding to the tube cross-section. At least one wall defining the groove of at least one of the end caps has projections at spaced locations, each shaped to provide a lead-in face and a rear retaining face. The sheet is provided with appropriately shaped apertures at spaced locations corresponding to the projections adjacent one end edge thereof, the arrangement being such that, in fitting the end cap to its adjacent tube end, the apertures of the tube end are guided by the lead-in and opposed faces of the end cap, to locate over and be positively retained by the retaining faces of their corresponding projections.