The present invention relates to apparatus for use in venting pipelines that have a plastic lining such as these used for transporting hydrocarbon fluids. A pipeline assembly comprises a pipeline (2), a corrosion resistance liner (3), and a micro-annulus (4) located between said pipeline and liner. The pipeline assembly also comprises a venting means (5) adapted for fitment in or through the corrosion resistance liner (3), wherein the venting means (5) allows gas to flow from the micro-annulus into the center of the pipeline assembly but not in the opposing direction.