A method of securing a cable (22) to a wind turbine blade is described. The method involves providing a pre-assembled cable assembly (34) comprising a cable (22) and a plurality of mounts (40a-e) pre-attached to the cable (22) at intervals along the length of the cable (22). The plurality of mounts (40a-e) is attached to a surface (20) of a wind turbine blade such that the mounts (40a-e) are spaced apart along the surface (20) of the blade. The spacing between adjacent mounts (40a-e) when the mounts (40a-e) are attached to the blade is less than the length of the cable (22) between said adjacent mounts (40a-e) such that a predetermined amount of slack is provided in the cable (22) between said adjacent mounts (40a-e). A pre-assembled cable assembly for use in the method is also described together with a method of assembling the cable assembly.