Premier Oil plc was an independent UK oil company with gas and oil interests in the United Kingdom, Asia, Africa and Mexico. It was devoted entirely to the 'upstream' sector of the industry — the exploitation of oil and gas — as opposed to the 'downstream' refining and retail sector. It was listed on the London Stock Exchange until it was acquired by Chrysaor Holdings and then merged into Harbour Energy in March 2021.
Two sanctioned Russian oligarchs have become co-owners of Britain's biggest oil producer after it completed a deal to buy the German company. LetterOne, an investment company partly owned by oligarchs Mykhailo Fridman and Petr Aven, now owns almost 15% of Harbor Energy. Harbor Energy is the largest producer of oil and gas in UK waters. It bought most of the oil and gas assets of the German firm Wintershall DEA from the chemical giant BASF.