A method of forming a wind turbine blade shear web flange section (36) by resin transfer moulding comprises providing a mould assembly (84) comprising a mould surface (86) defining a mould cavity and arranging a plurality of elongate flange elements (46) with the mould surface in an array (80) such that the flange elements are positioned one on top of another with first and second longitudinal ends (56,60) of each flange element longitudinally offset from respective first and second longitudinal ends of a neighbouring flange element so as to form a tapered portion (58,62) at each of a first and second longitudinal end of the flange section (36). A The method further comprises injecting resin to the mould cavity and curing the array of flange elements in a resin matrix to form a cured flange section having a laminate construction.