The Britannia field, discovered in the mid 1970s, is the first in the UK sector of the North Sea to be operated jointly by two companies, Conoco and Chevron, through the formation of the new operating company, Britannia Operator Limited. The platform contains utility, drilling and production facilities, together with a 140-man accommodation unit. The heaviest unit is the integrated deck, weighing 11,000t, which required maximum use of the lift (this was one of the largest semi-submersible crane vessels available).