Art collector Charles Saatchi is gifting more than 200 works and his Saatchi Gallery to the British public, it has been announced.
The artworks, including Tracey Emin's My Bed and Chapman brothers works, are worth more than £25m ($37.7m).
The 70,000 sq ft Saatchi Gallery in Chelsea, owned by Cadogan Estate, will become the Museum of Contemporary Art for London (Moca London).
The museum will meet all costs and "no charges will fall to the state".
The gallery's management are in talks with the government to find a department "which would own the works on behalf of the nation".
The gallery said in a statement that Saatchi felt it was "vital for the museum always to be able to display a living and evolving collection of work, rather than an archive of art history".
It said the gift would ensure that, when Saatchi retired, Moca would have "a strong, rotating permanent collection of major installations".
Moca will be free to display the works at all times as well as to lend them to other institutions.
Tracey Emin said she was thrilled by Saatchi's donation and wished "more people had that kind of vision".
A permanent collection of works by high-profile British artists, including Emin, forms part of Saatchi's gift.
It includes Richard Wilson's Oil Room installation which is currently on display at the gallery.
It also includes Tragic Anatomies, by Jake and Dinos Chapman, which features mutated mannequins in a garden, and an installation by Emily Prince made up of thousands of drawings of US military personnel killed in Afghanistan and Iraq.
A wall of bones which form the text of a Gandhi speech - by Indian artist Jitish Kallat - and French-Algerian artist Kader Attia's room of life-sized praying figures made from aluminium foil also form part of the collection.
Further gifted pieces which do not form part of the permanent collection could be sold by Moca to raise cash for new works.
New acquisitions will be added to the foundation's holdings, enabling the museum "to remain actively involved in the newest developments in contemporary art".
The gallery's managers say they will make sure free entrance continues by raising money from sponsorship and hosting events, and using revenues from its facilities.
Turner Prize winner Grayson Perry, whose pieces are among works gifted, said: "This is fantastic news - I'm very proud to be part of another national institution."
Culture Secretary Jeremy Hunt said: "Charles Saatchi has built up a collection of huge international importance.
"His decision to gift these works to the nation is an act of incredible generosity and I'd like to thank him on behalf of the government.
"Philanthropy is central to our vision of a thriving cultural sector and this is an outstanding example of how Britain can benefit from individual acts of social responsibility."