A gas turbine engine component comprising: a structure including spaced apart first and second exterior walls extending in a first direction to an endwall, the first and second exterior walls are joined at the endwall to provide a cooling cavity, the first and second exterior walls being a pressure and suction side walls, wherein the component is a blade that includes an airfoil that provides the structure; a wishbone baffle arranged in the cooling cavity and including first and second interior walls (96, 98) respectively adjacent to the first and second exterior walls, the first and second interior walls extending in the first direction to and joined by an apex to provide a first cavity, the wishbone baffle separates the first cavity from a second cavity provided between the apex and the endwall; and first and second passageways (120, 122) respectively arranged between the first interior and exterior walls and the second interior and exterior walls, the first and second passageways (120, 122) generally having a uniform width in the thickness direction that is perpendicular to a chord-wise direction, wherein the first and second exterior walls are not parallel to one another, wherein, a second portion of the structure has a width in a thickness direction that is at least twice a width of a first portion of the structure in the thickness direction, characterised in that at least one aperture is provided in the apex to permit fluid communication between the first and second cavities (102, 104), the wishbone baffle and the first and second passageways (120, 122) being arranged such that in operation a cooling fluid enters a blade root, then flows into the first cavity, and most of it travels around the wishbone baffle through the first and second passageways (120, 122) toward the second cavity, and the cooling fluid within the wishbone baffle between the first and second interior walls (96, 98) exits through the least one aperture and into the second cavity. a structure including spaced apart first and second exterior walls extending in a first direction to an endwall, the first and second exterior walls are joined at the endwall to provide a cooling cavity, the first and second exterior walls being a pressure and suction side walls, wherein the component is a blade that includes an airfoil that provides the structure; a wishbone baffle arranged in the cooling cavity and including first and second interior walls (96, 98) respectively adjacent to the first and second exterior walls, the first and second interior walls extending in the first direction to and joined by an apex to provide a first cavity, the wishbone baffle separates the first cavity from a second cavity provided between the apex and the endwall; and first and second passageways (120, 122) respectively arranged between the first interior and exterior walls and the second interior and exterior walls, the first and second passageways (120, 122) generally having a uniform width in the thickness direction that is perpendicular to a chord-wise direction, wherein the first and second exterior walls are not parallel to one another, wherein, a second portion of the structure has a width in a thickness direction that is at least twice a width of a first portion of the structure in the thickness direction, characterised in that at least one aperture is provided in the apex to permit fluid communication between the first and second cavities (102, 104), the wishbone baffle and the first and second passageways (120, 122) being arranged such that in operation a cooling fluid enters a blade root, then flows into the first cavity, and most of it travels around the wishbone baffle through the first and second passageways (120, 122) toward the second cavity, and the cooling fluid within the wishbone baffle between the first and second interior walls (96, 98) exits through the least one aperture and into the second cavity.