Largest archaeological excavation throws light on last 8.000 years at Heathrow

The largest single archaeological excavation in the UK, at the planned Terminal 5 at Heathrow Airport, has yielded an unprecedented insight into the way mankind has used the landscape over the last 8000 years.

A team of around 80 archaeologists has been working at the 100-hectare (250- acre) site of Terminal 5 for over a year and has found evidence of human activity going back to hunter-gatherers in the Stone Age, around 6,000BC, as well as Bronze Age, Iron Age, Roman, Saxon, Medieval and later remains. In all, 80,000 objects were found, including 18,000 pieces of pottery, 40,000 pieces of worked flint and the only wooden bowl found dating to the Middle Bronze Age (1,500BC-1,100BC).

Archaeologists have also been able to piece together a fascinating insight into changes in the way that people expressed their religious feeling towards the land as farming developed. They found field boundaries laid down as early as 2,000BC continued into the 20th century.

Archaeological excavation began at T5 in April 2002, with the construction work on the Terminal itself beginning in December 2002; the terminal is due to open in spring 2008.

No single archaeological unit had enough staff to tackle the project alone. Instead, two long-established practices, Oxford Archaeology and Wessex Archaeology, formed a joint venture called Framework Archaeology to work at T5 and all other BAA airports. The excavation was a major challenge to the staff, who worked amid the noise and fumes of the world´s busiest international airport.

The excavation:

* revealed objects including the only wooden bowl found dating to the Middle Bronze Age (1,500BC-1,100BC); one of only two wooden buckets from the same period; and a log ladder leading down into a pit dug during the Middle Bronze Age containing a wooden axe haft and a Neolithic stone axe, itself 2,000 years old when it was placed there. Two beautiful Iron Age pottery cups were also found.

* shed new light on the development of farming during the Bronze Age. Farming began during the Neolithic – New Stone Age – period (4,000BC- 2,400BC) when forests were gradually cleared and crops were planted and gathered communally. It had been thought that communal farming continued on open land until the Middle Bronze Age (1,500BC-1,100BC). However, at Terminal 5, pollen found from hedges used as field boundaries showed that people here were creating fields with boundaries from around 2,000BC, during the Early Bronze Age, 500 years earlier than archaeologists have previously thought.

* charted the changes in the landscape made by man from 6,000BC. These included: pits where meat was cooked by hunter gatherers during the Mesolithic (Middle Stone Age) period, c6,000BC, when the landscape was heavily forested; large ceremonial pathways created during the Neolithic era (New Stone Age, 4,000BC-2,400BC); fields and boundaries and the first small permanent settlements in the Bronze Age (2,400BC-700BC); and a small village in the Iron Age (700BC-AD43) and Roman times. The excavation reveals how the settlement died out at the end of the Roman era, but another settlement appeared in the mid-12th century. Some of the field boundaries created in the Bronze Age are still visible on maps and were still in use in the 20th century.

* revealed how the religious focus of people changed over the centuries. The excavation looked at the Stanwell Cursus, a four-kilometre (2.5 mile) pathway about 20 metres wide and flanked by ditches, which was built as early as 3,800BC and cuts across the Terminal 5 site. The cursus was a pathway with religious significance which linked important sites. The excavation revealed that when the first field boundaries were created in the Early Bronze Age (around 2,000BC – 1,500BC), they ran around the cursus and not across it, as a mark of respect for its religious significance. But during the Middle Bronze Age, from 1,500BC, field boundaries were created across the cursus itself, a sign that it was no longer venerated. At the same time, access to the local rivers for people´s livestock was harder because it would mean driving them across others´land, so waterholes were dug instead. These then became the focus of religious rituals, with important objects such as pottery and wooden objects placed in them as a sign of their religious significance. These changes show how man changed the religious significance of sites according to how useful they were to early farming.

The project was unique in the way that it integrated the archaeological and the commercial. Framework´s staff spent seven years designing and planning the project and working in the Heathrow area. The result was a focussed way of carrying out archaeology which allowed the excavators to know which areas were important and so avoid wasting time and money.

BAA encouraged the best archaeology possible. They hired archaeological consultant Gill Andrews and Professor John Barrett, from Sheffield University, who, together with Framework Archaeology, developed a unique working method at T5. By analysing and recording finds on site during excavation, rather than waiting until the end as is usual, staff were able to interpret their findings as they were made as well as ensuring that their work followed the most interesting and important directions. The excavation was rare in having computer terminals onsite and its own post- excavation department.

“The Heathrow excavation is a landmark in archaeology for many reasons,” said John Lewis, Framework manager.

“It is the largest single excavation in British archaeology, in terms of the huge area that was dug. It is the longest time – over a year – that such a large number of archaeologists, 80, were employed.

“It was fascinating to discover that within the boundaries of the world´s busiest international airport lies a record of how people used the landscape for 8,000 years, from the time when people were hunter gatherers to the earliest farmers and later.

“BAA have led the way in their method of integrating archaeology with construction work and allowing the full excavation of this site.”

Ken Welsh, the project manager, said: “The excavation revealed that the change from transient, mobile communities, where farming was carried out in short-lived clearings, to that of a settled agricultural economy with individually owned fields took place as early as 2,000BC. This is five hundred years before the accepted date.

“It also showed how the religious system changed under pressure from the new farming method. Land was needed so much that the cursus lost its significance and was used for growing crops. Instead, water for livestock became more difficult to get and waterholes were dug and became venerated sites – we find many valuable objects placed in them as a sign of their importance.”