A method of casting a component comprising: locating and maintaining a core in a fixed space relationship within the interior of a shell mould comprising: providing at least one pin (1A, 1B, 1C, 1D, 1E) extending into the core with at least one axial end of the at least one pin protruding from the core, forming a wax pattern having an outer surface by encasing the core and the at least one protruding axial end of the at least one pin in wax such that the at least one protruding axial end of the at least one pin terminates at the outer surface of the wax pattern; and forming said shell mould around said wax pattern such that, upon removal of the wax pattern, and in the subsequent casting process for the production of a hollow metal component, the at least one protruding axial end of the pin abuts the shell mould thus fixing the at least one pin and maintaining the position of the core relative to the shell mould, after forming the shell mould, removing the wax pattern to leave the shell mould containing the core, firing the shell mould, and pouring molten metal into the shell mould around the core, wherein the at least one protruding axial end of the at least one pin has an enlarged head portion (6A, 66A, 6A', 6B, 6B', 6C', 6D', 6E), wherein the material of the pin has a higher melting point than the temperature of the molten metal during casting, and wherein the pin is formed of recrystallized alumina. locating and maintaining a core in a fixed space relationship within the interior of a shell mould comprising: providing at least one pin (1A, 1B, 1C, 1D, 1E) extending into the core with at least one axial end of the at least one pin protruding from the core, forming a wax pattern having an outer surface by encasing the core and the at least one protruding axial end of the at least one pin in wax such that the at least one protruding axial end of the at least one pin terminates at the outer surface of the wax pattern; and forming said shell mould around said wax pattern such that, upon removal of the wax pattern, and in the subsequent casting process for the production of a hollow metal component, the at least one protruding axial end of the pin abuts the shell mould thus fixing the at least one pin and maintaining the position of the core relative to the shell mould, after forming the shell mould, removing the wax pattern to leave the shell mould containing the core, firing the shell mould, and pouring molten metal into the shell mould around the core, providing at least one pin (1A, 1B, 1C, 1D, 1E) extending into the core with at least one axial end of the at least one pin protruding from the core, forming a wax pattern having an outer surface by encasing the core and the at least one protruding axial end of the at least one pin in wax such that the at least one protruding axial end of the at least one pin terminates at the outer surface of the wax pattern; and forming said shell mould around said wax pattern such that, upon removal of the wax pattern, and in the subsequent casting process for the production of a hollow metal component, the at least one protruding axial end of the pin abuts the shell mould thus fixing the at least one pin and maintaining the position of the core relative to the shell mould, after forming the shell mould, removing the wax pattern to leave the shell mould containing the core, firing the shell mould, and pouring molten metal into the shell mould around the core, wherein the at least one protruding axial end of the at least one pin has an enlarged head portion (6A, 66A, 6A', 6B, 6B', 6C', 6D', 6E), wherein the material of the pin has a higher melting point than the temperature of the molten metal during casting, and wherein the pin is formed of recrystallized alumina.