University of Manchester archaeologists have started the excavation of an enormous building complex in Iraq, thought to be around 4,000 years old.

The team, directed by Professor Stuart Campbell and Dr Jane Moon, both from Manchester, and independent archaeologist Robert Killick, first spotted the amazing structure –thought to be an administrative complex serving one of the world’s earliest cities– on satellite.

It was after carrying out geophysical survey and trial excavations at the site of Tell Khaiber that they were able to confirm the size of the complex at about 80 metres square – roughly the size of a football pitch.

They are the first British archaeologists to excavate in Southern Iraq since the 1980s, working close to the ancient city of Ur, where Sir Leonard Woolley discovered the fabulous ‘Royal Tombs’ in the 1920s.

The arrangement of rooms around a large courtyard are at a site only 20km from Ur, the last capital of the Sumerian royal dynasties, the founders of the earliest cities in the world.

Professor Campbell is head of the University’s renowned Department of Archaeology. He said: “This is a breathtaking find and we feel privileged to be the first to work at this important site.

“The surrounding countryside, now arid and desolate, was the birthplace of cities and of civilization about 5,000 years ago and home to the Sumerians and the later Babylonians.”

One of the most striking finds at the site to date is a clay plaque, 9cm high, showing a worshipper approaching a sacred place. He is wearing a long robe with fringe down the front opening.

“It has been off-limits to international archaeologists for many decades so the opportunity of re-engaging with the study of the earliest cities is a truly exciting one,” said Professor Campbell.

“The satellite photos suggested the presence of a substantial building, and our survey has indeed confirmed that there is a building about 80m square, probably connected to the administration of Ur.

“We provisionally date the site to around 2,000 BC, the time of the sack of the city and the fall of the last Sumerian royal dynasty. “

The team aim to analyse plant and animal remains found at the site to help reconstruct environmental and economic conditions in the region 4,000 years ago.

Marshy conditions are thought to have prevailed, with the head of the Gulf being much further north, so that maritime trading was possible to obtain vital natural resources from India and the Arabian peninsula.

Professor Campbell, who has now returned from Iraq, added: “As well as offering unparalleled opportunities for redeveloping research in one of the most important areas of archaeology in the world, the project is also building partnerships with local practitioners and institutions.

“The aim is to help rebuild capacity in archaeological expertise and heritage management, working alongside members of Iraq’s State Board for Antiquities and Heritage, and to address the 20-year isolation from the international community.”