A tool for forming a composite component having a curved body and an integral flange (16, 18) from a pre-form, the tool comprising: a curved body portion having a lay-up surface; and a forming assembly having a lay-up configuration and a forming configuration, the forming assembly comprising: a plurality of forming elements each having a lay-up surface and a primary flange-forming surface, the forming elements being radially outwardly moveable from the lay-up configuration to the forming configuration, in which the forming elements are circumferentially spaced from one another; a plurality of filler elements each having a secondary flange-forming surface, the filler elements being arranged to move into the circumferential gaps between the forming elements in the forming configuration so as to form a substantially continuous flange-forming surface; and wherein each pair of adjacent forming and filler elements have complementary features (164, 166, 168, 170) arranged to engage with each other to axially align the elements (106, 107) relative to each other in the forming configuration; wherein in use a pre-form can be disposed on the layup surfaces (110, 120) of the curved body portion and the forming elements, and wherein movement to the forming configuration causes the pre-form to be deformed between the continuous flange-forming surface and a counteracting forming surface to form the integral flange (16, 18). a curved body portion having a lay-up surface; and a forming assembly having a lay-up configuration and a forming configuration, the forming assembly comprising: a plurality of forming elements each having a lay-up surface and a primary flange-forming surface, the forming elements being radially outwardly moveable from the lay-up configuration to the forming configuration, in which the forming elements are circumferentially spaced from one another; a plurality of filler elements each having a secondary flange-forming surface, the filler elements being arranged to move into the circumferential gaps between the forming elements in the forming configuration so as to form a substantially continuous flange-forming surface; and wherein each pair of adjacent forming and filler elements have complementary features (164, 166, 168, 170) arranged to engage with each other to axially align the elements (106, 107) relative to each other in the forming configuration; a plurality of forming elements each having a lay-up surface and a primary flange-forming surface, the forming elements being radially outwardly moveable from the lay-up configuration to the forming configuration, in which the forming elements are circumferentially spaced from one another; a plurality of filler elements each having a secondary flange-forming surface, the filler elements being arranged to move into the circumferential gaps between the forming elements in the forming configuration so as to form a substantially continuous flange-forming surface; and wherein each pair of adjacent forming and filler elements have complementary features (164, 166, 168, 170) arranged to engage with each other to axially align the elements (106, 107) relative to each other in the forming configuration; wherein in use a pre-form can be disposed on the layup surfaces (110, 120) of the curved body portion and the forming elements, and wherein movement to the forming configuration causes the pre-form to be deformed between the continuous flange-forming surface and a counteracting forming surface to form the integral flange (16, 18).