An electrically operated fluid flow valve arrangement (50) includes an electrically powered magnetic field generator (42), a valve body (44) defining a valve chamber (7), an inlet port (5), an outlet port (20) and a valve member (18) located in the chamber (7). The valve member (18) is movable between closed and open conditions relative to one of the ports (5, 20). The valve member (18) includes a permanent magnet (9). The arrangement (50) includes a switchable pole 46 formed of a ferromagnetic material. In use, in a first latched condition, the valve member (18) is retained by the switchable pole (46) in one of the closed or open conditions and, in a second latched condition, in the other of the closed or open conditions, the valve member (18) being moved from one latched condition to the other by operation of the generator (42).