Over the past decade fentanyl use has spiked, leading to tens of thousands of deaths in the United States. Most of the deadly drug enters the US via its border with Mexico, concealed deep within vehicles and even hidden inside food packages. The Trump administration has previously accused the Mexican government of colluding with the drug cartels. He’s now hoping that the threat of import tariffs on Mexico will stem the flow of the deadly drug into the US.

Jonny Dymond is joined by the BBC’s special correspondent Quentin Sommerville, who has been on the ground at the US-Mexico border and has visited one of the drug cartels’ operations. He also speaks to the BBC's Mexico and Central America correspondent Will Grant.

Producers: Richard Moran, Alice Aylett Roberts and Eleanor Sly

Sound engineer: James Piper

Assistant editors: Richard Fenton-Smith and Sergi Forcada Freixas

Senior news editor: China Collins