An apparatus for producing tubes formed from fibre reinforced composite material, the apparatus including: an elongate hollow mandrel (3) having an internal mandrel cavity (5), the mandrel having an external surface (7) upon which reinforcing fibre materia (9) can be wrapped to provide a composite lay-up (10) supported thereon; and fluid flow means (11) for enabling heat transfer fluid of different temperatures to be circulated through the mandrel cavity (5), such that when fluid at an elevated temperature is circulated, heat is transferred from the fluid, through the mandrel (3) to the composite lay-up (10) for curing or forming said lay-up.