A method of injection moulding an article, the method comprising the steps of: (a) providing an injection mould comprising a plurality of mould parts (4, 6, 8, 24, 26) defining a mould cavity of the injection mould, the plurality of mould parts including first and second movable mould parts (4, 6), wherein the second movable mould part is annular and wholly surrounds the first movable mould part, and the plurality of mould parts further includes at least one further mould part which is on an opposite side of the injection mould from the first and second movable mould parts (4, 6), the injection mould further comprising an injection inlet for injecting molten thermoplastic resin material into the mould cavity, wherein the injection inlet is located in the vicinity of the first movable mould part and the second movable mould part is remote from the injection inlet; (b) disposing the first and second movable mould parts (4, 6) in a first configuration so as to define a first intermediate moulding cavity, in which first configuration the first movable mould part is in a first rearward position and the second movable mould part is in a first forward position, wherein in the first configuration the first intermediate moulding cavity is defined substantially between the first movable mould part and the at least one further mould part, a moulding surface of the first movable mould part is located spaced from an opposite moulding surface of the at least one further mould part, and a moulding surface of the second movable mould part is located adjacent to the opposite moulding surface of the at least one further mould part; (c) injecting molten thermoplastic resin material into the first intermediate moulding cavity through the injection inlet to fill the first intermediate moulding cavity with the molten material; (d) closing the injection inlet; (e) after commencement of the injecting step and at least partly after the closing step, moving the second movable mould part from the first forward position to a second rearward position; (f) moving the first movable mould part from the first rearward position to a second forward position; and (g) moving the second movable mould part from the second rearward position to a third forward position thereby to dispose the first and second movable mould parts (4, 6) in a final configuration so as to define a final moulding cavity of the injection mould filled with the molten material, the final moulding cavity defining a cavity outer surface which defines the outer shape of the article to be moulded. (a) providing an injection mould comprising a plurality of mould parts (4, 6, 8, 24, 26) defining a mould cavity of the injection mould, the plurality of mould parts including first and second movable mould parts (4, 6), wherein the second movable mould part is annular and wholly surrounds the first movable mould part, and the plurality of mould parts further includes at least one further mould part which is on an opposite side of the injection mould from the first and second movable mould parts (4, 6), the injection mould further comprising an injection inlet for injecting molten thermoplastic resin material into the mould cavity, wherein the injection inlet is located in the vicinity of the first movable mould part and the second movable mould part is remote from the injection inlet; (b) disposing the first and second movable mould parts (4, 6) in a first configuration so as to define a first intermediate moulding cavity, in which first configuration the first movable mould part is in a first rearward position and the second movable mould part is in a first forward position, wherein in the first configuration the first intermediate moulding cavity is defined substantially between the first movable mould part and the at least one further mould part, a moulding surface of the first movable mould part is located spaced from an opposite moulding surface of the at least one further mould part, and a moulding surface of the second movable mould part is located adjacent to the opposite moulding surface of the at least one further mould part; (c) injecting molten thermoplastic resin material into the first intermediate moulding cavity through the injection inlet to fill the first intermediate moulding cavity with the molten material; (d) closing the injection inlet; (e) after commencement of the injecting step and at least partly after the closing step, moving the second movable mould part from the first forward position to a second rearward position; (f) moving the first movable mould part from the first rearward position to a second forward position; and (g) moving the second movable mould part from the second rearward position to a third forward position thereby to dispose the first and second movable mould parts (4, 6) in a final configuration so as to define a final moulding cavity of the injection mould filled with the molten material, the final moulding cavity defining a cavity outer surface which defines the outer shape of the article to be moulded.