A method of manufacturing an aerofoil structure capable of being diffusion bonded and superplastically formed to create a substantially hollow cavity within the aerofoil structure, the method comprising: providing a metallic plate for forming the aerofoil structure; joining mounting elements to opposing end surfaces of said metallic plate; dividing said plate along a plane extending substantially in a span-wise direction so as to produce two metallic panels each with one of said mounting elements joined thereto; assembling the two metallic panels so that the surfaces of the panels opposite to the surfaces which have been divided are facing each other; and joining the two metallic panels to one another to form the aerofoil structure; wherein the mounting elements are joined to one another to form the root of the aerofoil.