A flexible tension member for structural applications comprises twenty or more high strength rods (R) bundled helically with a lay length 20 to 150 times overall diameter, the rod (R) upon introduction being substantially free from curvature resulting in slackness in the bundle and introduced without flexural stresses significantly exceeding the yield point of the rod structure. The invention may utilize rods of solid circular or non-circular cross-section, or tubular and formed of metal, e.g., steel, and/or non-metallic material, more particularly fibre reinforced plastics, and results in a smooth uniform appearance, with good integrity and no signs of slackness despite the unusually long lay length employed.