Liquid fuel injection pumping apparatus

A liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine comprising an injection pump operable in use to deliver fuel in timed relationship with an associated engine, a low pressure supply pump for supplying fuel to the injection pump, valve means for controlling the output pressure of the supply pump, a resiliently loaded component defining a surface against which a control pressure can act to enable the amount of fuel supplied at each injection stroke of the injection pump to be varied, a control valve for deriving said control pressure from the output pressure of the supply pump, and a valve responsive to the pressure drop across said control valve, said valve being included in the flow path between the low pressure supply pump and the injection pump, said valve being arranged to prevent flow of fuel along said flow path in the event that the pressure drop across said control valve falls below a predetermined value.