North Sea oil
In 1964, well before North Sea oil was known about, he left Shell and became an independent geology consultant and in 1973 he founded Clyde Petroleum, which had many involvements in North Sea oil. While working with this company he was also an MP from 1974 to 1979. He became the company's Chief Executive from 1979 to 1983 and its Chairman from 1983 to 1995.