Seven months ago Nicolas Maduro seemed to be on the brink. A rival for the Venezuelan presidency, Juan Guaido, emerged out of nowhere and led the most serious challenge to Chavismo in 20 years. Weary Venezuelans dared to believe that they were finally to get a new government.

Today the picture is very different. Mr Maduro is still in power, peace talks are spluttering along in Barbados, and the US - which backs Mr Guaido - appears at a loss of how to loosen the Venezuelan leader’s vice-like grip on the country.

Yet for anti-narcotics agents, there is no mystery to the remarkable staying power of Mr Maduro: as the country crumbles around him, the 56-year-old, they say, is kept in power by a vast drug trafficking industry that has captured the state.

Figures are hard to come by but the United States estimates that a quarter of all Colombian cocaine passes through Venezuela, making it a key staging post in the worldwide trade.

But it is the structure of the business that sets Venezuela apart from most of the continent.