<p>A method and apparatus for mitigating slug formation in a multiphase fluid stream that is flowing through a conduit wherein the conduit comprises a first portion and a second portion which is upwardly inclined to the first portion and wherein the multiphase fluid stream comprises a gaseous phase and a liquid phase, the method comprising the steps of: (a) determining the pres- sure in the conduit upstream of a slugging zone; (b) determining the pres- sure in the conduit downstream of the slugging zone; (c) determining the ac tual pressure difference across the slugging zone by subtracting the down stream pressure from step (b) from the upstream pressure from step (a); (d) determining the error between a target pressure difference and the actual pressure difference; (e) producing a signal comprising a first component which is proportional to the error and a second component which is propor tional to the rate of change of the error over time; and (f) using the signal produced in step (e) to control the position of an adjustable choke valve b cated downstream of the slugging zone so as to stabilise variations arising in the actual pressure difference over time.</p>
