With more than three-quarters of global oil reserves controlled by governments, the options for the oil groups are diminishing. In a world of high oil prices, Canada’s Athabasca oil sands look like a godsend. Covering an area larger than England, they are estimated to contain at least 1,700bn barrels, – equivalent to all the conventional oil reserves in the world.

But fears over climate change mean sentiment has turned against many fossil fuel projects, as the recent protests in the UK over plans to build a new coal-fired power station at Kings-north in Kent have shown. A significant number of coal-fired plants in the US have also been abandoned or rejected recently.