In Russia we see the influence of the Arctic, and how its freezing climate limits Russia’s ability to be a truly global power. ... The chapter on the USA illustrates how shrewd decisions to expand its territory in key regions allowed it to achieve its modern destiny as a two-ocean superpower. Europe shows us the value of flat land and navigable rivers in connecting regions with each other and producing a culture able to kick-start the modern world, while Africa is a prime example of the effects of isolation.

A final reason is that Iran holds what might be a trump card – the ability to close the Strait of Hormuz in the Gulf through which passes each day, depending on sales, about 20 per cent of the world’s oil needs. At its narrowest point the Strait, which is regarded as the most strategic in the world, is only 21 miles across. The industrialised world fears the effect of Hormuz being closed possibly for months on end, with ensuing spiralling prices.