Disclosed is a flow separator, typically for use in separating liquid from gas in a flowing mixture of liquid and gas, e.g. water, oil and gas in a hydrocarbon well production fluid pipeline, the separator having a swirl generator disposed at the inlet to a cylindrical separation chamber and the separation chamber having an elongate liquid extraction slot formed along its wall, such that in operation the swirling flow centrifugally pushes the liquid towards the wall of the separation chamber to exit the separation chamber through the extraction slot into a collection chamber which may allow the return of the extracted liquid back into the main flow using a U-shaped tube.