The Markham field was discovered in 1984 and extends over license blocks 49/5a and 49/10b on the UK Continental Shelf and license blocks J3b and J6 on the Netherlands Continental Shelf. ST-1 comprises six wells and a single installation connected via two pipelines (12” and piggybacked 2” nominal bore) to the Markham J6A installation on the Dutch sector 5.6km (measured via pipeline length, 5km as the crow flies) from the ST-1 installation. The pipelines cross the median line into the Dutch sector and are covered by the Markham Treaty. A cessation of production justification report was submitted to OGA on 22 April 2016 and approved 11 August 2016. Formal cessation of production from ST-1 occurred 11 April 2016. The ST-1 installation and pipelines as well as the J6A installation are owned by the Markham partners. ST-1 was installed in 1994 and was a normally unattended installation (NUI) supported by a four-leg steel jacket in a water depth of 31m. Primary control was exercised from J6A. The decommissioned Stamford and live Grove pipelines cross the ST-1 to J6A pipelines in the J6A 500m zone in the NL sector. Historically the ST-1 installation also exported gas to J6A from the Windermere installation which is operated by INEOS UK SNS Limited. The Windermere installation, pipeline and umbilical are addressed by separate Decommissioning Programmes submitted independently by INEOS