The invention provides a method of manufacturing a wind turbine blade comprising a spar and at least one airfoil section, where both the spar and the airfoil section comprise an outer surface which forms part of an aerodynamically active surface of the blade. The method comprises steps of providing a support structure, placing the spar at the support structure, providing a clamp adapted to be fixed to the outer surface of both the spar and the airfoil section, arranging the airfoil section relative to the spar, fixing the clamp to the outer surface of the spar and the airfoil section, and assembling the at least one airfoil section an the spar by a process including adhesion.