A conductor is suitable for use in a high-voltage cable, and includes an aluminium alloy, in which the aluminium alloy comprises one or more of a group 3, 4 or 5 element and/or a lanthanide, each with a concentration in the range of 0.006 to 0.03% (m/m). The conductor has undergone a thermal treatment at a temperature from the range of 185° C. to 315° C. during a period from the range of 12 hours to 24 hours, so that the conductor has a conductivity of 61% IACS or more.