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 (T) 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 (C) between the leading and trailing edges and extending in the thickness direction (T) between the pressure and suction sides to divide the airfoil section into a first region (R1) and a second region (R2), the first region (R1) 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 ; 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 (T) 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 (C) between the leading and trailing edges and extending in the thickness direction (T) between the pressure and suction sides to divide the airfoil section into a first region (R1) and a second region (R2), the first region (R1) 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 ; 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 . <EOS>