Visitor numbers are soaring after the failed diamond robbery inside Britain's biggest tent. So what really happened ?

What the raid was all about - the exquisite Millennium Star diamond. The Millennium Star is a 203.04-carat, D-flawless pear-shape diamond which was purchased by a De Beers buying office in the Republic of Congo. The Steinmetz Group spent five months cutting and polishing it. "That stone is mindblowing, just astonishing," says a De Beers spokesman. The rest of the jewel collection includes 11 exceptionally rare blue diamonds, cut in a variety of shapes and weighing a total of 188 caratts. Another highlight of the collection is a 27.64-carat vivid blue heart-shaped stone dubbed the "Heart of Eturnity." The stones came from De Beer's Premier Mine in South Africa. The De Beers Millennium Jewels are being shown to the public for the first time at the Millennium Dome. De Beers says the value is without precedent, so any discussion of its value is "academic".

Events unfolded at 9.30am, half an hour after a powerboat glided up to Queen Elizabeth jetty and cut its two engines to avoid drawing attention. On the other side of the dome site, four men posing as builders revved a bulldozer, preparing, it seemed, for work on a nearby site. To the 64 visitors already touring the dome, the movements yesterday were without significance. To the Flying Squad, they signalled the imminent attempt to pull off the biggest robbery since the Brink's-Mat raid at Heathrow in 1983. At 9.30, the gang made an audacious and extraordinary move: the digger clattered at full pelt into the wire fence, crushing it flat before startled security guards. It then charged towards the dome's money zone. In the mayhem, four masked men slipped through the narrow door of the diamond vault and headed for what they thought was the Millennium Star, a diamond so distinctive that it could never be sold on the open market. In fact, they were looking at a replica - the 12 diamonds had been replaced with crystal copies the day before, following a police request. Once inside, the robbers had effectively imprisoned themselves within the 4ft concrete walls. Without a lookout standing guard, they hammered on the reinforced glass cases with hammers, sledgehammers and electric nailguns. Armed police surrounded the vault and ordered them to drop their weapons and come out.

The raid had been anticipated for months following a tip-off to the Metropolitan police, thought to have been from a paid informer. An operation involving 100 officers from London and Kent - codenamed Magician - was set up in total secrecy. The Cabinet Office and senior figures in the New Millennium Experience Company, including Pierre-Yves Gerbeau, and the mining company De Beers, which owns the diamonds, were informed. The commissioner of the Metropolitan police, Sir John Stevens, was also briefed.

The decision to allow the raid to take place was a risky one, especially as schoolchildren were in the dome when the raid occurred. However, the officer in charge of the investigation, Detective Superintendent Jon Shatford, said it was the only way to gather compelling evidence. Police refused to be drawn last night on whether the attempted heist was the work of sophisticated criminals or "chancers". Some aspects bear striking resemblances to the recent James Bond movie The World Is Not Enough. "It is obvious there was a good degree of planning," a source said.

Police arrested four men in the vault, another one at a motorboat which had been moored to the Queen Elizabeth II pier next the Dome, and another on the north bank of the Thames at Lower Lee Crossings, opposite the dome. This suspect is believed to have been monitoring police messages. Altogether eight men have been remanded in custody. Six of the men were charged with attempting to rob the diamonds, belonging to De Beers, valued in excess of £200m on 7th November. A father and son from Kent were charged with aiding and abetting the attempted robbery. Security was tight at Belmarsh Magistrates Court as the men appeared in the dock and spoke only to confirm their names. The six men charged with attempted robbery are: