Prime Minister Gordon Brown witnessed the groundbreaking, and met workers on site. "The Olympic and Paralympic Games will mark a fantastic celebration in 2012 as Britain hosts the world's greatest sporting event. The Games offer a unique opportunity to change the lives of young people through sport and the positive effects will be felt long after the Games have finished.
"The early start to building work on the Olympic Park site is good news, taking us another step closer to 2012 and the regeneration of one of the country's most deprived areas. I have no doubt that the construction of the new permanent venues, infrastructure and transport links within the largest new urban park to be created in Europe for 150 years will be a catalyst for lasting social and economic change in east London."
The first phase of construction involves reinforcing the ground on which the Stadium will sit upon by inserting up to 4,000 concrete columns into the soil. This forms the permanent foundations for the Stadium structure.
Through the autumn and winter of 2008, floor slabs will be laid for the base of the Stadium 'bowl' and the lower tier structures, and the columns that support the pedestrian concourse level will be built.
Early in 2009 the erection of the steel structures that will support the Stadium roof will begin to rise, giving an indication of the final height and scale of the structure.
ODA Chairman John Armitt said: "Over the next year the Olympic Stadium structure will begin to emerge from the ground.
"People will be able to see with their own eyes a stadium which is designed to be different – an innovative and sustainable design which uses temporary elements to meet a complex brief – a stadium built for both Games and legacy.
"It is great news that we can make an early start but this is a project with an immovable deadline so we know there are big challenges ahead."
Chairman of the London Organising Committee Sebastian Coe said: 'The Olympic Stadium will be the jewel in the crown of the Olympic Park. It will be a fantastic centrepiece for track and field in the summer of 2012 and provide a lasting legacy for athletics in the UK for generations to come.
'Construction is starting early and as the building work takes shape over the next three years, we will be working hard on our plans to make sure we deliver a truly memorable Games for the Olympic and Paralympic athletes who will take centre stage in the Stadium at Games time, and for the communities who will use the Stadium in legacy.'
Olympics Minister Tessa Jowell said: "Starting work early on the Stadium is a tremendous achievement and is a real indication of our progress, with all our major milestones met. I would like to congratulate the ODA and all the workers on site who have done fantastic job.
Mayor of London Boris Johnson said: "As I told the International Olympic Committee this week, I am determined to make sure that London does the Games proud, and that the Games leave a lasting legacy which every Londoner can enjoy and be proud of."
Olympic Stadium facts and figures:
- More than 1,000 construction workers will be based on the Stadium site;
- 33 buildings on the Olympic Stadium site have been demolished;
- Over 800,000 tonnes of soil has been taken away to help create the construction platform for the Stadium
- The Stadium is highly sustainable, containing around 10,000 tonnes of steel - the lightest Olympic Stadium to date;
- The total Stadium island site covers an area of 16.2 ha
- The Stadium is 53m high - slightly taller than Nelson's Column
- The Stadium roof covers an area of 24,500 sq metres
Contractor - Sir Robert McAlpine Ltd;
Architect and sport venue design - HOK Sport Ltd;
Structural and building services engineer - Buro Happold;
Landscape architect - HED;
Planning consultant - Savills Hepher Dixon