A 4,000-year-old Egyptian statue sold by Northampton Museum has been bought by a private collector, it has emerged.
Auction house Christie's of London said the buyer wanted to remain anonymous.
The statue of Sekhemka, court official and priest, which sold for £15.76m, will now vanish from public view, campaigners said.
An ancestor of Lord Northampton donated the statue in 1850. The family will get 45% of the sum after earlier saying the council had no right to sell.
The sale was labelled a "shameful and unethical act" by the Egyptian Embassy.
The Save Our Sekhemka Action Group said: "The people of Northampton have been robbed in broad daylight of the jewel in the crown of their museum.
"This looks like the worst possible outcome for the world of Egyptology.
"There is now no guarantee that the statue of Sekhemka will ever be seen again, even by professional researchers, let alone by the children who might be inspired to find out more about the riches of Egyptian history and culture."
The Arts Council is to review the museum's accreditation in the light of the sale at a meeting on Thursday.
Loss of Arts Council England accreditation would make the museum ineligible for a range of future grants and funding. However, the leader of the Conservative council, David Mackintosh, said he did not see why this should happen.
Northampton Museum funding:
- £900,000 annual budget, according to Northampton Borough Council
- £166,000 granted in 2012 by Arts Council England for two projects and £69,000 granted in 2014 to digitise the museum's collection of 10,000 shoes online
- £615,000 Heritage Lottery Fund total grants for various projects
He said the money from Sekhemka's sale would be used to redevelop the existing museum building.
Scott Furlong, of Arts Council England, said: "It is very disappointing that the local authority committed to the sale and entered into an agreement with an auction house before our discussions with them were concluded."