A blade for a gas turbine engine comprises an aerofoil body having a suction side, a pressure side, and a trailing edge. An internal cooling passageway is provided in the aerofoil body, and an ejection slot in fluid communication with the cooling passage and provided at the trailing edge of the aerofoil body. The ejection slot is defined between a pressure side wall and a suction side wall. Both the suction side wall and the pressure side wall include a mid-section and a trailing edge section adjacent the mid-section, and the thickness of the suction side wall and the pressure side wall reduces to define a taper with a wedge angle less than or equal to 20 degrees.