An aerofoil blade or vane suitable for the turbine of a gas turbine engine includes an extending aerofoil portion having facing wall parts interconnected by a divider member to partially define first and second cooling fluid passage portions. The first and second passage portions are interconnected in a series fluid flow relationship by a bend passage portion. The first passage portion directs cooling fluid to the bend portion and the second passage portion exhausts cooling fluid from the bend portion. The divider member provides a localised contraction of the downstream end of the first passage portion to accelerate the cooling fluid flow before it enters the bend passage portion. The divider member provides a localised progressive series narrowing and opening of the upstream end of the second passage portion in the general direction of cooling fluid flow.