One consequence of the cumulative Opec takeover in the 1970s was to extend state ownership to about 85 per cent of world oil-producing capacity. The member countries’ nationalisations altered the ownership of about 50 per cent; other state-owned companies in the market economies rose to about 10 per cent of the total; and production in the then Communist countries, which had been only about 17 per cent of world output in 1970 but was rising much faster, reached nearly a quarter of the total by 1979. In 1989, even outside the Soviet Union, the proportion of state ownership was close on 60 per cent. Much of the 40 per cent of world capacity of which private owners retain sole or partial ownership is in North America.

That is capacity. The ensuing shares of actual production were somewhat different. Most of the extra capacity developed since the Opec nationalisations has been by private companies. Nearly all the capacity producing private ‘equity crude’, ever since, has been fully employed. During the early 1980s some of the state-owned capacity, notably in the Soviet Union, China and Mexico, was fairly fully employed too. But by 1985 the rest, essentially in Opec, was not much more than half-employed. By the end of that decade, recovery in world demand, setbacks in some non-Opec supply, had brought Opec production back to some 85 per cent of capacity, even before the Gulf war. That was mainly due to higher output in member countries. But it was also partly due to sizeable downward revisions in Opec capacity, mainly in the Gulf, and after 1990–1 the removal of Kuwaiti and Iraqi supplies from the market.