Dubai police have discovered a shipment of Captagon pills — estimated to cost more than a billion dollars — hidden in a shipment of doors and building panels, in one of the largest drug seizures in the Gulf countries.

68 million tablets of the highly addictive amphetamine were brought through Dubai's Jebel Ali in 5 shipping containers weighing more than 13 tons.

The value of one pill for the shipment, which was confiscated by the authorities, was estimated at about $12, although it could reach $25 in neighboring Saudi Arabia. Authorities in Dubai said the detainees belonged to an "international criminal organisation".

Most of the world's Captagon is produced in Syria, the world's largest drug trafficker, since President Bashar al-Assad saw an opportunity to make money as the economy collapsed after civil war erupted in 2011.

Most of the world's Captagon has been produced in Syria, the world's largest drug trafficker, since President Bashar al-Assad saw an opportunity to make money as the economy collapsed after civil war erupted in 2011.

Since 2011, hundreds of millions of these pills have been smuggled into Jordan, Iraq, Saudi Arabia and other Gulf Arab states, where they are consumed by people who work in physically demanding jobs to keep them alert.

It also says that during the war against Islamic State in Iraq and Syria, the use of pills was common among fighters on all sides who wanted to remain vigilant and alert.

Although massive seizures of cereals hidden in everything from pomegranates to milk cartons are in ports from Sicily to Dubai, despite airstrikes on their production facilities and Jordanian forces shooting smugglers, the Captagon trade continues to expand.

It was former West German scientists who invented Captagon in the sixties to treat attention deficit disorder, but it became illegal by 1986, and now the value of this illegal trade is estimated at £8.1 billion.

The British government announced in March that it was imposing sanctions on a number of Syrians and Lebanese, including businessmen, militia leaders and several of Assad's cousins, for allegedly being heavily involved in the manufacture and sale of Captagon.