As Opec and Russia prepare to meet in Vienna next month to discuss raising oil output, three strongman leaders will loom over proceedings. Russian president Vladimir Putin, Saudi Arabia’s crown prince Mohammed bin Salman and US president Donald Trump may make awkward bedfellows, but it is their voices that will be heard loudest at the meeting, however indirectly. All three lead nations are capable of producing more than 10m barrels a day of crude or, collectively, more than a third of global output.

But each has different goals that are placing strains on the original late-2016 deal between Opec and a Russian-led consortium of other big producers. Whose voice wins out will probably determine the direction of oil prices in the coming months. For Saudi Arabia’s energy minister Khalid al-Falih, the most powerful figure within the 14-member Opec cartel, the situation represents a narrow tightrope to walk if he is to cement his reputation as a master of petro-diplomacy. Having played a critical role in bringing Russia into the fold back in 2016, Mr Falih is now tasked with protecting an oil price recovery to near $80 a barrel that is helping fund expensive social and economic reforms that Mr Salman is trying to push through in the kingdom.

At the same time he needs to placate a hot-tempered US president who is leaning on the kingdom to make sure petrol prices do not leap higher ahead of US midterm elections this year. While the US is not involved in the deal, its shale industry has undoubtedly benefited from the price recovery it has fostered, but politically that has taken a back seat for Mr Trump as average national pump prices approach $3 a gallon.