Venezuela sits on top of what are potentially the world’s largest reserves of crude oil, which are not only handily located next door to the world’s largest energy consumer, the US, but are also mostly undeveloped.

So it may seem surprising that in June this year two of the US’s biggest oil companies, ExxonMobil and ConocoPhillips, walked away from multibillion-dollar oil projects in the Orinoco belt, the jewel in the crown of Venezuela’s oil industry.