The first underground tunnel which will carry power lines needed for the 2012 Games and its legacy has been completed in east London.
Lord Coe inspected the first cable tunnel to be completed
Organisers, the Olympic Delivery Authority (ODA), say this will allow construction work on the Olympic Park to begin next summer.
ODA chief executive David Higgins also announced 10 milestone targets, to be achieved by the 2008 Beijing Games.
He said it was a "tough challenge" but he was confident each one would be met.
Milestones for the next phase include the site of the Olympic Park being cleared and cleaned, and power lines being switched from overhead pylons to underground.
The main temporary roads and bridges are to be built and new water and energy systems installed.
And construction must have started on the Olympic Village and on the footbridge between Aquatics Centre and the Olympic Stadium by the time the Games in Beijing begin.
ODA chief executive David Higgins said: "In our first year we have hit every milestone on the project. We now move to the next strategic phase 'Demolish, Dig, Design'.
"This is an extremely challenging project, but by setting out the programme of work in this transparent way we believe that we are breaking new ground for a project of this scale.
"We will be allowing people to judge progress for themselves against the significant investment that is being made."
Olympics Minister Tessa Jowell said: "However we are not complacent and recognise that there is still much to do.
"The milestones published today set out clearly the next steps and demonstrate how the fantastic progress we have already achieved will continue."