A method of manufacturing a foam body having an anisotropic cell structure, the method including the steps of: expanding a polymer at an elevated temperature to form an initial foam body; and cooling the initial foam body under a negative pressure. There is also provided a method of manufacturing a foam body having an anisotropic cell structure, the method including the steps of: (a) in a first expansion step, expanding a foamable polymer composition substantially isotropically to form an initial foam body having an isotropic cell structure; and (b) in a second expansion step, expanding the initial foam body anisotropically in a selected direction under a negative pressure which applies an expanding force in the selected direction to provide a final foam body having an anisotropic cell structure. Apparatus for the methods are also disclosed.