For Saudi Arabia, a recent shipment of pomegranates from Lebanon found to be stuffed with more than 5m white amphetamine pills known as captagon was the last straw. The kingdom responded by banning all Lebanese fruit and vegetables.

In the past year, Saudi customs agents have found 54m captagon pills - an amphetamine popular with fighters across the Middle East as well as wealthy young men in the Gulf - in grapes, apples and potatoes shipped from Lebanon to the Red Sea port of Jeddah.

Riyadh’s retaliation is a painful blow to farmers already reeling from the country’s economic crash. The ban was necessary, Saudi’s interior ministry said, because Lebanon had failed to stop the drug trafficking, “despite the kingdom’s numerous attempts to urge the concerned Lebanese authorities to do so, and in order to protect the kingdom’s citizens and residents from anything that might affect their safety and security”.

The captagon shipment is the latest sign of a growing narcotics trade in crisis-hit Lebanon and war-torn Syria, which share a porous border and whose legitimate economies are both collapsing.

Last year authorities in Europe and the Middle East seized 34.6 tonnes of Syrian-origin captagon pills, with “a theoretical street value as high as $3.46bn”, according to an analysis published recently by the Center for Operational Analysis and Research, a political risk consultancy. That compares with the combined exports of both countries — less than $5bn in 2019, the last year for which figures are available.

“The crisis in both countries is transforming the type of economy to something . . . not only informal but illegal and criminal,” said Samir Aita, a Syrian economist based in France.

Captagon, originally developed in the 1960s as a medical treatment, is now made mostly in Syria. It has long been associated with the decade-long civil war, taken by fighters on the battlefield to score a euphoric high, suppress appetite and sharpen concentration.

Over the past two years, with economic crises in Lebanon and Syria worsening, the captagon trade has metastasised, said Caroline Rose, senior analyst at think-tank Newlines Institute. “Not only are the [pills] being shipped in industrial-sized quantities [to Europe and other places in the Middle East], they’re also camouflaging it in licit substances.”

Last September Romanian law enforcement found almost a tonne of captagon pills and 1.5 tonnes of hashish concealed in soap bars on a ship that had set off from the Syrian port of Latakia. Greek port authorities in 2019 found more than five tonnes of captagon tablets worth more than $650m in containers carrying building materials. The vessel had also come from Latakia.

There is little known European market for this drug, so analysts speculate they may have been intended for onward shipping to Libya or other conflict areas, or else sent to Europe in order to conceal their country of origin in an effort to fool authorities in the Gulf.

The huge scale of these hauls from Syria has led many to conclude that Bashar al-Assad’s regime, which has regained control of two-thirds of the country, is complicit in the trade.

“The regime is very desperate for any kind of revenue stream under the pressure of sanctions and the wartime economy,” said Rose, who has been researching the regional narcotics trade. “They have these state tools to be able to export this on an industrial level.”

Analysts in Lebanon place the blame for the trade on Hizbollah, the powerful Iran-backed paramilitary group, considered a terrorist organisation by states including the US. It is also a key political player in Lebanon and an ally of Syria’s regime. The party denies involvement in illegal activity.

“Is Hizbollah alone the guy who is doing that?” asked Aita, the economist, pointing out that the chemicals used to make captagon are imported from neighbouring countries including Turkey. “Everybody is implicated.”

The main export market for captagon is wealthy, often bored, young men in the Gulf, who pay $10 to $25 for a pill, according to figures cited in research published in the International Addiction Review journal.

There is little reliable public information on the scale of drug use in Saudi Arabia specifically, although research has estimated that as many as three-quarters of Saudi patients treated for drug addiction are on amphetamines, “almost exclusively” captagon. In 2015, a Saudi prince was arrested in Lebanon attempting to smuggle two tonnes of pills aboard a private jet. The so-called Captagon Prince was released last year.

But for many Saudis concerned about an alarming increase in drug abuse among young people, the import ban ticks several boxes, most obviously sending a clear indication of its determination to crackdown on the illicit trade.

“There are concerns that there could be dozens of other undetected shipments,” said Mohammed Alyahya, editor-in-chief of the Saudi-owned Al Arabiya English news network. “Saudi Arabia loses very little by banning all imports.”

The hamstrung Lebanese government has pledged to bring smuggling under control. Between July 2019 and June 2020, Lebanese authorities seized nearly 2m captagon pills. But according to a former Lebanese law enforcement official who asked not to be named, corruption inside the security forces makes it difficult to combat the illicit narcotics trade.

“Corruption is so high,” the former official said. “It’s Escobar,” he added, referring to the infamous Colombian drug lord.

Politicians in Lebanon caution that the ban will not be effective. “Saudi Arabia and all the Gulf countries know well that a ban on Lebanese produce will not stop drug smuggling and [that] co-operation between us will help stop these networks,” said Hassan Diab, Lebanon’s caretaker prime minister.

Additional reporting by Miles Johnson in Rome and Simeon Kerr in Dubai