A structural reinforcement for a hollow section at least part of at least one of whose surfaces is the internal surface of an external panel comprising a rigid reinforcing member having a shape that substantially conforms to the cross section to be reinforced. An expandable adhesive material is provided over a portion of the surface of the rigid reinforcing member and the shape of the rigid reinforcing member and the amount and location of the expandable adhesive is such that upon foaming the foam contacts and bonds to the internal surfaces of the hollow section other than the interior surface of the external panel. In this way deformation of the external body panel during the foaming and/or cooling of the foamed expandable material is reduced or prevented.