Abstract: A filled hollow fibre composite material is made by laying up a plurality of prepreg plies (1) of hollow fibre composite material and non-stick film material (2) one on top of another with the non-stick film material (2) interleaving successive plies (1) at selected areas thereof. The laid up interleaved plies are treated to resin bond the ply areas (3) not interleaved with the non-stick film material and leave the interleaved areas (4) unbonded. The so formed laminate is treated at edge regions to expose open unfilled hollow fibre ends (5, 6) and the plies in the unbonded interleaved areas (4) are separated at the non-stick film material (2) to provide access to the open hollow fibre ends (7) in each ply for the introduction of a film material into the hollow fibres through the open hollow fibre ends (7) in one or more of the separated plies (1) to form a filled hollow fibre composite material.