A fresh round of expropriations in Venezuela has raised fears that the Opec producer’s already declining oil output could sink to its lowest level in the past 20 years.

Troops were mobilised over the weekend to assist Venezuela’s state-owned oil company, PDVSA, in seizing the assets of some 60 oil service companies, after a law was approved last week that paves the way for the state to take increasing control over its all-important oil industry.