A wire strand (10) comprises a plurality of wires (12, 16, 20). The wires comprise a central king wire (12), a first layer (14) of wires (16) arranged around the king wire, and a second layer (18) of wires (20) arranged around the first layer. The king wire is formed of steel having a carbon content of at least 0.3 wt %. Each wire of the first layer is formed of steel having a carbon content which is less than the carbon content of the king wire. Each wire of the second layer is formed of steel having a carbon content which is greater than, or the same as, the carbon content of the wires of the first layer.