A North Sea gas platform leaving dry dock at Graythorp near Hartlepool, County Durham
Crude oil and natural gas were discovered beneath the seabed of the North Sea in the early 1960s. Political upheaval in the Middle East during the 1970s affected the supply of fuel from there and made it more secure and profitable to exploit these natural resources in the North Sea. Much of Britain's fuel supply still comes from the North Sea. This concrete structure was built by John Laing Plc for Hamilton Brothers Oil and Gas Ltd. It would be towed out to the Ravenspurn North Gas Field in the North Sea, sunk and fixed to the seabed. This substructure would support the platform for the gas extraction plant.