Its not fixed cost, its GMP (Guaranteed Maximum Price). That means that if the stadium stays exactly as it is in design and construction, it will cost no more than £Xm. Essentially, the Main contractor takes the risks and responsibility on board. The stadium could still cost more though, and that is in the case of design changes for which the client is responsible as t would be unreasonable to expect the main contractor to take the responsibility and risk of that. That's why its cost certainty, as we will have the opportunity to spend more if we have the ability to, and we will have control over the amount extra that we spend by simply adding or not adding what we want.