The report details:

· damage to the dragons decorating the Ishtar Gate, one of the world's most famous monuments, from attempts to prise out the relief-moulded bricks

· broken bricks inscribed with the name of Nebuchadnezzar lying in spoil heaps

· the original brick surface of the great processional route through the gate crushed by military vehicles

· fuel seeping from tanks into archaeological layers

· acres of the site levelled, covered with imported gravel - which Dr Curtis said would be impossible to remove without causing further damage - and sprayed with chemicals which are also seeping into the unexcavated buried deposits

· thousands of tonnes of archaeological material used to fill sandbags and mesh crates, and equally damaging, when that practice stopped, thousands more tonnes of material imported from outside the site, contaminating the site for archaeologists forever.

Babylon, capital of the Babylonian empire, site of the Tower of Babel and the Hanging Gardens of Babylon, one of the seven wonders of the ancient world, was rediscovered by archaeologists in the 19th century, but has inspired legends for thousands of years. It was the capital of two of the most famous kings of all time, Hammurabi, who ruled from 1792 to 1750BC, and introduced the world's first code of law, and Nebuchadnezzar, ruler from 604 to 562BC, who rebuilt and doubled the size of the city and built the hanging gardens.

Dr Curtis, head of the Department of the Ancient Near East at the British Museum, has worked as an archaeologist in Iraq for decades, and directed many excavations.

He was back in Baghdad in 2003 as soon as the bombs stopped falling, when the British Museum led the international effort to assess the damage and losses from the looted national museum. He returned to Babylon last month at the invitation of the Iraqi authorities, and inspected it with a team of Iraqi archaeologists. However, he was still not able to inspect the entire site, as part of it is still fenced off and mined.

He therefore warns - in what one archaeologist who has read the report described as "the killer phrase" - that his report "should not be seen as exhaustive, but is indicative of the types of damage caused".

The military camp was established by the American forces in April 2003, and damage was already visible when Dr Curtis first visited part of the site that June. The same contractors, Kellogg, Brown and Root - a subsidiary of the American civil engineering corporation Halliburton, of which the US vice-president, Dick Cheney, is a former chief executive officer - were used to develop and maintain the site throughout, as it grew to a 150-hectare camp, housing 2,000 soldiers. This was officially handed over to Polish forces in September 2003.

His 14-page report, which includes maps and was compiled during a site visit in December, lists dozens of examples of visible damage. In a walk through the ancient city he observes damage to:

The Ishtar Gate

One of the most famous monuments of antiquity. It was excavated in the 19th century by German teams; the upper glazed parts of the gate are in a Berlin museum. However, the monument was so important to the Babylonians that the foundations, deep underground and never visible in antiquity, were also decorated with beautifully modelled dragons and inscriptions. He reports 10 separate areas of damage to the moulded brick reliefs. "It has been suggested that most of the damage [to figures on the gate] was caused ... by a person or persons trying to remove a decorated brick," he says.

The "Warsaw" Gate

Two 20-metre long trenches have been dug here. "In the piles of spoil alongside the trenches there are many fragments of brick, some with inscriptions of Nebuchadnezzar," the report says. One brick clearly has an inscription which reads: "Nebuchadnezzar, King of Babylon, who provides for Esagila and Ezadila, the el dest son of Nabopolassar, King of Babylon, am I."

The "Reno" gate

At one point, outside the base entrance nicknamed the "Reno Gate", he found a 200-metre stretch of road, lined with the mesh baskets "that have clearly been filled with deposits from the Babylon site, containing sherds, bones, etc."

The processional street

Two areas of 6th century BC brick pavement, part of the processional street, are exposed in this area. "In both cases the bricks are badly broken. This is thought to be the result of a heavy vehicle or vehicles driving over them. If this is so, it is likely that the bricks still covered by earth are similarly damaged."

The Ziggurat

Trenches have been dug into the ziggurat, one of the stepped pyramids which were one of the most distinctive Babylonian monuments and gave rise to the legend of the Tower of Babel. "Much pottery and many fragments of brick with cuneiform inscriptions of Nebuchadnezzar were observed in the bank of spoil" next to the trench.

Other observations include: an old car park vastly expanded to make a helicopter landing zone and parking lot, all flattened and gravelled, old tracks covered in new stones, now deeply rutted from heavy vehicles, large areas scooped out to a depth of two metres to obtain material to fill the sand bags and metal baskets and earth mounded up to protect six fuel depots, which also show evidence of leakage.

The most serious damage may be invisible, the contamination and disturbance of areas which have never been excavated, which may mean that many of the secrets of Babylon, including the site of the hanging gardens, may never be resolved.

In his conclusions Dr Curtis says: "A full-scale international investigation should be launched into the damage done to the archaeological site of Babylon during its occupation by coalition forces."

All mines and ordnance must be cleared, and all disturbed areas investigated and recorded by archaeologists appointed by the Iraqis, he says.

Babylon has never been on the Unesco list of world heritage sites. "Now more than ever Babylon needs the care, attention and advice that being a world heritage site would ensure it received," he says.

Dr Curtis said it was not possible for him to determine at which time, and by which forces, damage was caused: a separate report has been compiled by Polish archaeologists. A further report is being compiled by the Iraqis on the damage to Saddam Hussein's palace, built in a corner of the site, and which had already been looted before allied forces began camping out in the shell. The site had such symbolic importance to Saddam that he rebuilt many of the walls and gates, using bricks stamped with his name, many of which have been stolen.