Ascot will try to stage this year's Royal meeting behind closed doors due to the coronavirus pandemic.
The Guineas meeting at Newmarket and Derby meeting at Epsom have both been postponed due to the outbreak.
The five-day Royal Ascot fixture is a renowned social occasion, as well as featuring some of the biggest races of the Flat season but, if it goes ahead, members of the public will not be permitted to attend.
Guy Henderson, Ascot's chief executive said: "For public health and safety reasons, we have reached the difficult but unavoidable conclusion that Royal Ascot 2020 (June 16-20) will not be able to take place as an event open to the public.
"This will of course be a great disappointment for everyone planning to attend.
"It may prove possible to run the Royal Ascot races behind closed doors, dependent on Government and public health policy and the approval of the British Horseracing Authority for us to restart racing.
"This would be for the benefit of the industry, our valued partners and suppliers and our television audiences at home and internationally.
"Planning for this is now our complete focus and we will update on progress as and when we can."
Henderson also outlined the expected financial consequences of the decision.
He added: "The pandemic will have a significant financial impact on our business in 2020, along with so many others.
"Nevertheless, Ascot Racecourse will come through this crisis and we look forward to being able to welcome racegoers back when it is safe to do so.
"Meanwhile, our thoughts are with all those grieving and suffering as a result of COVID-19.
"We offer heartfelt thanks to our wonderful NHS staff, key workers and volunteers for all their selfless dedication."