A switchover valve for switching over from one supply of pressure fluid to another supply thereof in response to failing or failure of the one supply. The valve has a valve body having two inlets for connection thereto of the respective pressure fluid supplies and an outlet. A valve member is movable in the valve body between a position establishing communication for delivery of fluid from one inlet to the outlet and blocking flow from the other inlet to the outlet and a position establishing communication for delivery of fluid from the other inlet to the outlet and blocking flow from the one inlet to the outlet. The valve member is subject to pressure of fluid supplied to the one inlet for moving it from the first-mentioned position to the second-mentioned position and to pressure of fluid supplied to the other inlet for moving it from the second-mentioned position to the first-mentioned position. A latch for latching the valve member in one or the other of its positions is movable between a latching position engaging the valve member and a retracted position clearing the valve member for movement. The latch is biased toward the retracted position and is held in latching position against the bias by pressure of fluid delivered by the valve member in one or the other of its positions. The latch moves to the retracted position under the bias upon a drop in pressure of fluid delivered by the valve member in either of its positions.