The Dome, which has been looking increasingly grubby in recent weeks, is to be painted a bright "sunrise" hue, which will be floodlit at night.
Officials became concerned that its white "self-cleaning" skin had not been doing so as effectively as they had hoped. Their eye-catching solution is designed to counteract the build-up of dust from building works at the Greenwich site.
They had originally planned to send teams of cleaners up "with mops" to restore the exterior when the works were complete. Now it is hoped the paint job will make the structure stand out even more against the London skyline.
The New Millennium Experience Company, the firm which runs the Dome, intends to stage nightly light shows, using filters to change the yellow to other colours including blue, its second corporate shade.
"It will not be a luminous, day-glo colour, it will be a sunrise yellow that will change colour at night," said one Whitehall source, adding confidently: "It will solve all the cleaning problems."
Last year Peter Mandelson, while minister responsible for the Dome, announced that yellow would be the "official colour" of the Millennium. Posters advertising celebrations will also be in yellow and enormous yellow banners will be hung around the site.
But while planners regard the colour as "bright and optimistic", traditionally yellow symbolises jealousy and cowardice; in France, simply, it signifies treason.
The task of painting the biggest roof in the world yellow will be no mean feat. It covers 20 acres and is the largest fabric structure on earth. It is also strong enough to support a Jumbo Jet - theoretically, at least.Reuse content