Progress on the Stadium site will surge ahead this week as work completes to dig the Stadium bowl and the site offices are established for workers.

Ground levels have had to be lowered by nine metres to create the sunken area for the track and permanent lower tiers of seating. This means that over 800,000 tonnes of soil – enough to fill the Royal Albert Hall nine times over – has had to be been taken away from the Stadium area over the last three months to be reused elsewhere on the site.

Before construction begins, work will continue to create the podium level and form the Stadium construction platforms. Approximately 6,500 cubic metres of concrete will be recycled from other parts of the site and crushed to form a solid platform to support construction works.

ODA Chairman John Armitt said: 'We have investigated the Olympic Stadium site, demolished tens of buildings and excavated 800,000 tonnes of soil.

'Now that we have finished the work to dig the bowl where the opening and closing ceremony and athletics will take place in 2012, we are firmly on track to start construction work ahead of schedule.'

The site offices for the Olympic Stadium workers have also been constructed ready for numbers to dramatically increase. At the peak of the construction of the Olympic Stadium, there will be well over 1,000 staff based in the site offices, ranging from engineers and architects to foremen and digger drivers. The first 50 are expected to be move to the offices next month.

The Olympic Stadium is largely an island site surrounded by waterways and is contaminated from many years of previous industrial use. Highly-sensitive monitoring has been carried out on the site during the earthworks programme and this has detected small amount of low level radiological finds in the soil in the area. This soil, with mild radioactive properties present due to the past industrial activity over the last 100 years or so, is being managed so that it presents no risk to public or workers.

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