Sebastian Coe is confident the London Olympics in 2012 will not be overshadowed by drug cheats or "seedy chemists".
Lord Coe announced construction of the aquatics centre was to start two months early and discussed progress in the milestones leading up to the event - but focus was inevitably on sprinter Dwain Chambers at the High Court as he fought his Olympics ban.
As chairman of the 2012 Games, Lord Coe is determined to emphasise the legacy of the Olympics in London and has previously stated that Chambers' challenge would only further "damage" the image of athletics.
He said: "Drug cheats can never be allowed to be the large part of the story. The largest part of the story is the 99% of competitors who openly understand that competition is about fair, open endeavour.
"They understand the most talented, the hardest working and the ones with the best coaches and the smartest sports administrators make it to the top.
"There is no room for seedy chemists sitting in laboratories trying to figure out how to subvert that process."
He added: "Most people see these as two separate issues, the Games is fundamentally about national spirit, the belief that sport matters and the intrinsic values of sport are fundamental - 99% of the athletes and 99% of the population get that.
"Of course we take very seriously the need to deliver a Games in a drug-free, zero-tolerance environment. That is exactly what we will be aiming for over the next four years."
The Olympics Delivery Authority (ODA) said construction of the aquatics centre was to start earlier than planned as progress had been made at the site.
Lord Coe and Olympics Minister Tessa Jowell were delighted with the progress made. In a years' time they hope that almost all the Olympic Park will be cleared and cleaned. Other milestones include the foundations of the Olympic Stadium and the completion of the aquatic centre, and work will start on the velodrome and press centre.
