As pointed out in Chapter 5, issues surrounding the development of natural gas fields are characterised by a symbiotic relationship between buyer and purchaser. This symbiotic relationship introduces another institutional element into the picture. In addition to intra- and intercompany dynamics, opportunity costs, preferences, group behaviour, and the like, a new factor comes into play, the conflict of institutional interests between the sellers of natural gas and the buyers. In the case of southern North Sea gas fields, this clash was caused by the divergent commercial interests of the groups selling the natural gas and the Gas Council (later the British Gas Corporation), a state-owned entity since the end of the Second World War. These interests have both strategic and tactical aspects.