THE collapse of the top of Silbury Hill last year, which left a huge crater, is nothing new historian Brian Edwards has revealed.

His research has found the top had caved in on at least two previous occasions. The first collapse in the 1930s is well documented, but Mr Edwards from Devizes has discovered there was another collapse a century previously.

He will be talking about his latest research when he gives a talk, Silbury Hill: The Hole Story, at the Bradleian Hall at Marlborough College tomorrow. There are still some tickets (£4.50) available for the talk which starts at 8pm.

Mr Edwards, a mature student at the University of the West of England where he is studying for a PhD, has come across historic papers showing that a huge crater was recorded on top of the hill in 1849.

He was surprised, he said, to come across a drawing made in August 1849 by the Rev Lucas of Great Bedwyn, which shows clearly a collapse on the summit of the hill, very similar to last year's when a 300-year-old exploratory shaft dug by treasure hunters gave way.

Mr Edwards said: "I had been looking for some time for the drawing made in 1849, when they were digging a tunnel into the hill and broke through into the shaft. I found a copy with a dotted line showing a huge crater on the hilltop.What it shows is a big crater but what it does not tell us is whether the original 1777 shaft was ever filled in, or whether it was left open and the crater drawn in 1849 was the result."