Walking among the giant red sand dunes of Saudi Arabia’s Empty Quarter, Ali al-Ajmi, who manages the Shaybah oilfield, one of the largest in the kingdom, likens the work to “building something on Mars”.

“It is really a difficult area,” says Mr Ajmi of the Rub’ al-Khali desert, where some 350km of the world’s largest sand dunes separate the nearest town from Shaybah, whose temperatures in summer rise above 55ºC.