Cairo: Daesh has established a “ministry of antiquities” to maximise the profits from looting priceless artefacts across the territory it controls.

Elsewhere in the Middle East, ministries of this kind try to protect antiquities; Daesh’s version was set up to pillage and smuggle these treasures.

The trade has raised tens of millions of dollars for Daesh — a sum comparable to the profit the terrorists have made by the kidnap and ransom of Western hostages.

Since its lightning sweep through Iraq and Syria last year, Daesh has sought to transform itself into an organisation capable of ruling its own state, setting up an elaborate hierarchy of leadership and ministries.

In a territory replete with classical ruins, Daesh’s “ministry of antiquities” is doing its best to promote smuggling. “They happened upon a pre-existing situation of looting and turned it into a highly organised trade,” said Amr Al Azm, a former official in the Syrian antiquities ministry who now runs a network of archaeologists and activists to document the destruction of the country’s treasures.

In Iraq, the radicals have desecrated and looted the Assyrian remains at Mosul, Nimrud and Hatra. Earlier this month, they captured the Roman city of Palmyra in Syria, raising fears that it might suffer the same treatment.

When Daesh set up its self-described “Islamic Caliphate”, it imposed a 20 per cent tax on looted antiquities. The militants then tried to gain control of the trade by regulating access to ancient sites.

By last summer, various “antiquities ministries” had been established across their strongholds. They have since been drawn together to form part of a “Ministry for Precious Resources”, according to Aymen Jawad Al Tamimi, who has helped to gather an archive of Daesh’s operational documents.

The Sunday Telegraph has obtained Daesh-stamped licences, issued by the “antiquities ministries” in the Syrian cities of Aleppo and Deir Al Zor, giving permission to excavate archaeological materials, apparently in return for money.

In some areas, workers have been contracted to carry out digs, helped by local archaeologists who identify the most lucrative sites.

Accurate estimates for the revenue raised through this trade are hard to establish. But the Financial Action Task Force, an inter-governmental body, has put the figure at tens of millions of dollars.

Experts say the focus on figures distracts from the human consequences of the smuggling trade. “The bottom line is that it’s funding terrorism — and the deaths of Iraqi and Syrian people,” said Michael Danti, an archaeologist at Boston University who is advising the US State Department on how to tackle the problem. Daesh is believed to have developed a network of middlemen for the onward trade of the artefacts, providing one dealer with an armed escort for trips to the Turkish border.

In other cases, local people sell the treasures to middlemen, paying Daesh a tax of at least 20 per cent on the profits. The spoils have also been found in the possession of senior commanders. When US commandos killed Daesh’s alleged chief financial officer, Abu Sayyaf, on May 16, they discovered various relics inside his home, including an ancient Assyrian Bible.

Archaeologists say they are beginning to find evidence of organised pillage on a scale unseen throughout the Syria’s civil war. In Daesh-controlled territory around the ancient Mesopotamian city of Mari, founded in 300BC, more than 1,300 excavation pits have been dug in recent months, according to satellite imagery.

“As it became more sophisticated, we started to see machinery being used. If you were a contractor with your own machinery, you could bring that to dig. But if you weren’t, Daesh would lend you its own machines for a greater fee,” said Dr Azm, formerly of the Syrian antiquities ministry.

For as long as the militants control this territory, experts say that governments must do more to prevent the passage of looted antiquities across their borders. A draft United Nations resolution would ban the trade in any antiquities originating from Syria. But this measure has not yet been passed by the Security Council.

Dr Azm believes the ramifications of Syria’s cultural catastrophe will outlast its war. “One day, this conflict will end, and when it does, Syrians are going to need to rally around something in order to rediscover a common national identity,” he said. “When your past has been destroyed, what basis is there for people to want to live together again?”