Abstract: A method, system, controller and computer program product, for controlling the flow of a multiphase fluid comprising gas and liquid in a conduit, which conduit is provided at a downstream side with a flow restriction and a valve having a variable aperture, which method comprises the steps of selecting a flow parameter of the multiphase fluid in the conduit as a function of a pressure difference over the flow restriction; selecting a setpoint for the flow parameter; allowing the multiphase fluid to flow at a selected setpoint of the aperture of the variable valve; determining the pressure difference over the flow restriction and determining an actual value of the flow parameter from the pressure difference, without using a measurement of another variable in order to determine an actual gas/liquid ratio pertaining to the pressure difference at the flow restriction; controlling the flow of the multiphase fluid by determining a deviation of the flow parameter from its setpoint, determining an updated setpoint for