A gas turbine engine blade comprising: an airfoil (16, 40, 60) extending radially from a base to a blade tip (28, 41, 72, 114, 134), the airfoil comprising: a pressure sidewall (17, 47, 68) and a suction sidewall (19, 49, 66) each extending between a leading edge (18, 48) and a trailing edge (20, 50) opposite the leading edge; an internal cooling circuit (22, 70) extending from the base to the blade tip; and a squealer tip (24, 42, 62) comprising: a first squealer tip rail (25, 45, 74, 116, 136) and a second squealer tip rail (26, 46, 76, 118, 138) adjacent to the first squealer tip rail; and a squealer tip cap (27, 78, 120, 140) extending between the first and second squealer tip rails, wherein the blade tip, the first and second squealer tip rails, and the squealer tip cap define an internal squealer tip cooling channel (44, 64, 110, 130) and wherein the blade tip defines a supply aperture (52, 86) that fluidly connects the internal cooling circuit (22, 70) and the internal squealer tip cooling channel; characterised in that the first squealer tip rail, the second squealer tip rail, and the squealer tip cap comprise a presintered preform, wherein the presintered preform includes particles of an abrasive ceramic. an airfoil (16, 40, 60) extending radially from a base to a blade tip (28, 41, 72, 114, 134), the airfoil comprising: a pressure sidewall (17, 47, 68) and a suction sidewall (19, 49, 66) each extending between a leading edge (18, 48) and a trailing edge (20, 50) opposite the leading edge; an internal cooling circuit (22, 70) extending from the base to the blade tip; and a pressure sidewall (17, 47, 68) and a suction sidewall (19, 49, 66) each extending between a leading edge (18, 48) and a trailing edge (20, 50) opposite the leading edge; an internal cooling circuit (22, 70) extending from the base to the blade tip; and a squealer tip (24, 42, 62) comprising: a first squealer tip rail (25, 45, 74, 116, 136) and a second squealer tip rail (26, 46, 76, 118, 138) adjacent to the first squealer tip rail; and a squealer tip cap (27, 78, 120, 140) extending between the first and second squealer tip rails, wherein the blade tip, the first and second squealer tip rails, and the squealer tip cap define an internal squealer tip cooling channel (44, 64, 110, 130) and wherein the blade tip defines a supply aperture (52, 86) that fluidly connects the internal cooling circuit (22, 70) and the internal squealer tip cooling channel; characterised in that the first squealer tip rail, the second squealer tip rail, and the squealer tip cap comprise a presintered preform, wherein the presintered preform includes particles of an abrasive ceramic. a first squealer tip rail (25, 45, 74, 116, 136) and a second squealer tip rail (26, 46, 76, 118, 138) adjacent to the first squealer tip rail; and a squealer tip cap (27, 78, 120, 140) extending between the first and second squealer tip rails, wherein the blade tip, the first and second squealer tip rails, and the squealer tip cap define an internal squealer tip cooling channel (44, 64, 110, 130) and wherein the blade tip defines a supply aperture (52, 86) that fluidly connects the internal cooling circuit (22, 70) and the internal squealer tip cooling channel; characterised in that the first squealer tip rail, the second squealer tip rail, and the squealer tip cap comprise a presintered preform, wherein the presintered preform includes particles of an abrasive ceramic.