An airfoil for a gas turbine engine comprising: an airfoil section comprising a platform, a tip, a pressure side, a suction side, a leading edge and a trailing edge, wherein the airfoil section extends in a radial direction from the platform to the tip, and extends in a thickness direction between the pressure side and the suction side that meet together at both the leading edge and the trailing edge; wherein the tip comprises a floor and defines a tip pocket extending inwardly from the tip to the floor; and wherein the airfoil section includes a purge partition extending in a chordwise direction between the leading and trailing edges (162LE, 162TE) and extending in the thickness direction between the pressure and suction sides (162P, 162S) to divide the airfoil section into a first region and a second region, the first region defines at least one internal cooling circuit, the second region defines a purge cavity, the purge partition defines a first set of apertures that fluidly couple the at least one internal cooling circuit and the purge cavity, and the purge cavity extends along the floor between the leading and trailing edges (162LE, 162TE); wherein the airfoil section defines a purge slot along an external wall that bounds the purge cavity; and the airfoil section defines a second set of apertures in the floor that fluidly couple the purge cavity and the tip pocket; the airfoil being characterised in that a total cross-sectional area of all of the second set of apertures is greater than a combined sum, the combined sum defined as a total cross-sectional area of all of the first set of apertures and a cross-sectional area of the purge slot, and wherein the cross-sectional area of the purge slot is greater than a cross-sectional area of each of the first set of apertures. an airfoil section comprising a platform, a tip, a pressure side, a suction side, a leading edge and a trailing edge, wherein the airfoil section extends in a radial direction from the platform to the tip, and extends in a thickness direction between the pressure side and the suction side that meet together at both the leading edge and the trailing edge; wherein the tip comprises a floor and defines a tip pocket extending inwardly from the tip to the floor; and wherein the airfoil section includes a purge partition extending in a chordwise direction between the leading and trailing edges (162LE, 162TE) and extending in the thickness direction between the pressure and suction sides (162P, 162S) to divide the airfoil section into a first region and a second region, the first region defines at least one internal cooling circuit, the second region defines a purge cavity, the purge partition defines a first set of apertures that fluidly couple the at least one internal cooling circuit and the purge cavity, and the purge cavity extends along the floor between the leading and trailing edges (162LE, 162TE); wherein the airfoil section defines a purge slot along an external wall that bounds the purge cavity; and the airfoil section defines a second set of apertures in the floor that fluidly couple the purge cavity and the tip pocket; the airfoil being characterised in that a total cross-sectional area of all of the second set of apertures is greater than a combined sum, the combined sum defined as a total cross-sectional area of all of the first set of apertures and a cross-sectional area of the purge slot, and wherein the cross-sectional area of the purge slot is greater than a cross-sectional area of each of the first set of apertures.