the folded container illustrated in fig1 has a substantially rectangular base panel 1 , four side panels 2 stacked on top of the base panel , and four two - part side support tubes 3 upstanding from the corners of the base panel , each support tube having a lower member 4 adjacent to the base panel and an upper member 5 remote from the base panel . the support tubes 3 have a circular cross section but it will be understood that other suitable cross sections may be used . the upper member 5 is pivotally secured to the lower member 4 and is folded onto the surface 6 of the upper stacked side panel . the base panel 1 , side panels 2 and side support tubes 3 are formed from metal sheet material . referring to fig2 , each of the side panels 2 in the unfolded container occupies the space between two adjacent side support tubes 3 onto which the side panels are pivotally mounted , as will now be described . fig3 shows a side panel 2 having a terminated longitudinal slot 7 in one edge 8 . a similar slot is located in the opposing edge of the side panel . four pairs of laterally projecting cylindrical pins 9 , 10 , 11 and 12 are located on the lower members 4 of adjacent support tubes as shown in fig4 . each pair of pins is located at a different distance from the base panel with respect to any of the other pairs . preferably the first pair of pins 9 closest to the base panel are located at a distance t - s / 2 from the base panel , where t is s + r , s is the thickness of a side panel , and r is the distance between adjacent side panels , the second pair of pins 10 at a distance 2t - s / 2 from the base panel , the third pair of pins 11 at a distance 3t - s / 2 from the base panel , and the fourth pair of pins 12 furthest from the base panel are at a distance 4t - s / 2 from the base panel . each side panel 2 is mounted onto adjacent support tubes 3 by engagement of the relevant pair of slots 7 in the side panel edges 8 with a corresponding pair of cylindrical pins 12 as shown in fig1 . each slot 7 is closed at opposing ends to retain the pin 12 associated therewith . the pins 12 engage with the slots 7 in a free sliding fashion so that the side panel 2 can undergo translational movement in the slot plane as well as pivotal movement about the pin axis . the spacing of the pairs of pins 12 from the base panel 1 ensures that in the folded state the side panels 2 stack together in different horizontal planes overlying the base panel 1 as shown in fig1 . referring to fig5 and 7 a , the upper member 5 of a side support tube 3 has an extension 50 formed by a pair of opposed flat surfaces 13 projecting from its lower end with a longitudinal opening 14 therein . part of the wall of the lower member 4 of the side support tube 3 projects vertically from its upper end to form two opposing end pieces 15 , each end piece having a circular hole 16 located therein as shown in the mutually orthogonal side views of fig5 and 6 . the opposing end pieces 15 define a recess 17 , which partially extends into the tubular lower member 4 , and which is dimensioned so as to receive the extension 50 of the upper member 5 in close fitting engagement , with the holes 16 aligning with the longitudinal opening 14 of the extension 50 . a cylindrically cross sectioned bar 18 projects laterally through opposing holes 16 and opening 14 so as to retain the upper member 5 of the side support within the lower member 4 . the bar 18 is in sliding engagement with the extension 50 so that the upper member 5 can be vertically extended with respect to the lower member 4 ( fig7 a ). referring to fig7 a and 7 b the side support 3 can be moved from a substantially vertical unfolded position to a folded position substantially perpendicular to the lower member 4 by extending the upper member 5 until the lower edge 19 of the extension 50 is clear of the upper edge 20 of the lower member followed by rotation of the upper member 5 about the axis of the bar 18 . in erecting the container from a collapsed , folded condition , a first step is to rotate the upper members 5 of the four side support tubes 3 in turn from the folded position , where the upper members 5 are lying on the surface 6 of the uppermost side panel 2 as shown in fig1 , to the unfolded position where the upper members 5 are substantially vertical and form continuous columns with the corresponding lower members 4 as shown in fig8 . in a second step each side panel 2 of the container is moved in turn from a folded to an unfolded position and preferably fastened to adjacent side support tubes 3 before the next side panel is unfolded . there are two alternative methods for performing this step as shown in fig9 and in fig1 , 12 respectively . in a first method the edge 21 of the uppermost side panel 2 furthest from the side support tubes 3 onto which it is mounted is raised and rotated upwards towards the side support tubes 3 ( shown in fig9 ). when the side panel 2 is in a substantially vertical position , with the opposing edges 8 parallel to the corresponding side support tubes 3 , the side panel 2 is lowered vertically towards the container base panel 1 and into the unfolded position with a bottom edge 22 of the side panel resting on the upper surface of the base panel 1 ( shown in fig1 ). the side panel 2 is then fastened to adjacent side support tubes 3 by sliding engagement of bolts 34 secured to the side panel 2 within corresponding recesses 37 in the side support tubes 3 . the process is repeated for the remaining side panels in turn . in a second method the uppermost side panel 2 is slid in a substantially horizontal plane outwards between the side support tubes 3 onto which it is mounted ( shown in fig1 ). when the side panel 2 has been translated in this plane as far from the side support tubes 3 as the slots 7 in the edges 8 will allow , the edge 23 of the side panel 2 furthest from the side support tubes 3 is raised and rotated upwards towards the side support tubes 3 ( shown in fig1 ). when the side panel 2 is in a substantially vertical position , with the opposing pivoting edges 8 parallel to the corresponding side support tubes 3 , the side panel 2 is lowered vertically towards the container base panel 1 and into the unfolded position with the bottom edge of the side panel resting on the upper surface of the base panel 1 . the side panel 2 is then fastened to adjacent side support tubes 3 as described in the first method . the process is repeated for the remaining side panels in turn . a cover panel 30 is pivotally mounted onto the side panel 2 that is uppermost when the container is in the folded state by pivoted arms 24 as shown in fig1 - 15 . each arm 24 has a pin 29 arranged to co - operate with a slot 31 in opposing edges 32 of the cover panel 30 . the arm 24 also has an arcuate slot 25 cooperating with a pin 27 extending laterally through the curved slot 25 and in free sliding engagement therein . the arm 24 is secured to the edge 8 of the side panel 2 by a pin 26 ( fig1 a ). the arm 24 can be partially rotated from a vertical position by pivoting about the pin 26 and sliding of the pin 27 through the slot 25 as shown in fig1 b . when all four side panels 2 have been moved from the folded to the unfolded position the upper edge 33 of the cover panel 30 is moved from a position substantially parallel to the major face of the side panel onto which it is mounted to an angled position by rotation of the arm 24 about the pin 26 as described above as shown in fig1 . the cover panel 30 is then moved upwards and away from the side panel 2 as shown in fig1 by rotation about the pin 24 and sliding of the pin 24 along the slot 31 in the edge 32 of the cover panel 30 until it is resting on the upper edges of a front side panel 35 and a rear side panel 36 and substantially parallel to the container base panel 1 as shown in fig1 . the container is unfolded to a collapsed condition by reversing the steps described above . the person of ordinary skill in the art will appreciate that many modifications to the described embodiment are possible without departing from the spirit and scope of the invention defined in the appended claims . for instance wheels can be adapted to the base panel ; the side support tubes may have any suitable transverse cross section ; although the panels are preferably formed from metal , they could be formed of plastics or any other suitable material ; the container can be suited for different uses and be of different sizes .