SILBURY HILL -- WHY THE BRONZE AGE MONUMENT
4,500 year old hill from collapsing - 10 months and £1m over budget.
Jim Leary, the archaeological director for English Heritage throughout the work, thinks he has solved a riddle which archaeologists have fretted over for centuries: why thousands of people piled up 35 million baskets of chalk into the largest artificial hill in Europe, now part of the Stonehenge World Heritage site. It wasn't the final structure, but the staggering contribution of work which was important, he now believes, marking a site of immense but only guessable significance to the hunters and farmers of Bronze Age Wiltshire.
After following their predecessors into the heart of the monument, and then leaving the warren of Georgian, Victorian and 20th century tunnels packed again with chalk slurry so that they hope nobody will ever follow in their footsteps, the archaeologists and engineers are convinced there is no secret chamber, prehistoric passage or treasure hoard, only the hill itself rising 40 metres above the Wiltshire watermeadows, by the shoulder of the modern A4 following the line of the Roman road which jinked to avoid it.
Leary, announcing his preliminary findings to a meeting of the Society of Antiquaries in London, thinks the builders were revering the site - overlooking both sacred springs, and the source of the Kennet which he believes was then seen as the source of the mighty Thames - by joining in a spectacular communal effort, continued over generations. Even before the first hill rose, he has discovered a dense layer of compacted clay, which appears to be the result of thousands of feet trampling - or dancing - across the site.
Leary now believes there were scores of Silburies, some left for long periods, others worked on
continuously. His research is a by-product of eight years of near disaster for Silbury, since incredulous English Heritage and National Trust authorities heard that a gaping hole had opened at the summit in the torrential rains of the year 2000: the Duke of Northumberland's 1776 shaft, believed securely filled centuries earlier, had collapsed. While they were still debating what to do, there was a further collapse, swallowing the temporary cover. Further
collapses followed, and a remote camera probe uncovered to their horror a series of spreading voids inside the hill.
Last May, Skanska Engineering reopened the 1849 tunnel dug by Dean Merewether, and the 1960s BBC tunnel, to get into the hill and start plugging the holes: the work was planned to last only a few months, but the worst summer floods on record followed, and further collapses forced everyone off the site. Once back in, they were confident of finishing by Christmas - and then a further hole opened in the flank, as another void reached the surface. When completion was finally announced last week, the project had cost at least three times the original £500,000 budget.
Post excavation work will continue for years on the land snails and broken sarsen stones, wisps of still green grass and beetle wings taken from the heart of the hill. Nothing has been left behind except a cable to monitor movement - which they hope will lie idle. They hope that a job begun 4,500 years ago is complete, and no man will ever set foot inside Silbury Hill again.