A method of injection moulding an article from a water- soluble polymer, said method comprising: providing a mould comprising a male portion and a female portion defining a mould cavity, said portions being movable relative to one another to vary the volume of the mould cavity, injecting molten water-soluble polymer into the mould when the male portion and female portion are in a first position, and initiating relative movement of the male portion and female portion to reduce the volume of the mould cavity so as to force the molten water-soluble polymer already in the mould cavity into at least part of the remainder of the mould.