A method of making a spar cap (146) for a wind turbine blade comprises: (a) providing a plurality of elongate pultruded fibrous composite strips (100), each strip being of substantially constant cross section defined by first and second mutually opposed and longitudinally extending sides (102. 104) and by first and second longitudinal edges (110, 112), the first and second sides comprising, respectively, first and second planar abutment surfaces (118), the strip being of substantially uniform thickness between the first and second abutment surfaces, a first edge region (120) of the strip comprising a first edge of the strip being of relatively reduced thickness, the first side of the strip comprising an edge surface (122) adjacent the first abutment surface in the first edge region of the strip, and the strip having a first peel ply layer (114) at least partially covering the first abutment surface and at least partially covering the edge surface; (b) removing the first peel ply layers from the respective strips; (c) stacking the strips in a mould such that the first abutment surface of each strip abuts an abutment surface of an adjacent strip in the stack to define an interface region (142) between the strips, and such that a clearance region (144) is defined between the first edge region of each strip and an edge region of an adjacent strip in the stack; (d) supplying resin to the respective clearance regions and causing the resin to infiltrate into the interface regions between adjacent strips; and (e) curing the resin to bond the strips together.