Abstract: A pressure protection system (32) has a docking manifold (44) to which an upstream portion (36) and a downstream portion (38) of a pipeline (34) are connected. Also connected to the docking manifold (44) is a retrievable module (64) which has a conduit circuit (66) that connects the upstream and downstream portions of the pipeline (34) enabling fluid to flow between the two portions (36, 38). The conduit circuit contains two fail-safe valves (72) which are controlled by a control module (80) within the retrievable module, and two pressure transmitters (76) co-operable with the control module (80). When wither pressure transmitter (76) senses fluid pressure in the conduit circuit (66) to be above a threshold value then it causes the control module (80) to effect closure of the valves (72) preventing the pressure rise from reaching the downstream portion (38) of the pipeline (34).