A mould for forming a collapsible container from an expandable material, the container comprising, at least a base and two pairs of a side walls extending at right angles from opposing sides of the base, the mould comprising: a first mould member and a second mould member movable with respect to each other between an open and a closed moulding position to define a mould cavity; and a plurality of anvils mounted on a rear surface of at least one of the first mould member and/or second mould member, each anvil being movable so as to be extended into the mould cavity so as to form one or more hinges in the expandable material at predetermined locations within the mould cavity; wherein the mould cavity defined by the first mould member and the second mould member is a three-dimensional representation of an inside-out configuration of the assembled container.