An aerofoil blade or vane for the turbine of a gas turbine engine includes: an aerofoil leading edge; an aerofoil trailing edge; an aerofoil suction side; and at least one reverse-pass coolant passage, extending within the aerofoil blade or vane; wherein the at least one reverse-pass coolant passage includes a substantial reverse-pass portion in which, in use, coolant flows in a direction away from the trailing edge and towards the leading edge.