The owners of the building which houses Charles Saatchi's art collection have won a High Court battle to evict him.
The Gallery opened on London's South Bank in April 2003
A judge upheld the claim by Japanese company Shirayama Shokusan that the London Saatchi Gallery had continually breached the term of its lease.
The judge said Danovo, the firm which runs the gallery, had shown "deliberate disregard" of the owners' rights.
The breaches included putting works in areas for which they had not paid rent and offering a two-for-one ticket deal.
The judge ordered the gallery, which is considering taking the case to the Court of Appeal, to pay damages totalling £9,750 for using rooms and moving works of art into areas not included in its lease.
The collection includes works by modern artists Marc Quinn and Tracey Emin.
Damien Hirst's work has been exhibited at the Saatchi Gallery
Shirayama Shokusan took the action jointly with Cadogan Leisure Investments, which manages County Hall, the South Bank building which once housed the Greater London Council.
The claimants said the gallery also erected advertising signs without permission outside the gallery.
Cadogan said the ticket price deal breached the lease because the rent calculations were based on a set entrance fee.
Judge Sir Donald Rattee upheld the claim that Danovo had forfeited the lease.
He admitted his ruling would have an effect on visitors to the gallery and the 80 staff who worked there.
Mr Saatchi did not attend court to give evidence about his allegations that his staff had been harassed by the landlord and owner.
He is planning to move his main artworks to a new gallery in Chelsea.
Jit Chauhan, managing director of landlord Cadogan, said the company was "delighted" with the case's outcome.
"We have had a difficult time attempting to deal with Mr Saatchi and his staff and are relieved that the gallery will be leaving County Hall," he said.
London Mayor Ken Livingstone condemned the court's decision, calling the move "a disgrace".
"The gallery opened up many parts of County Hall that had remained restricted to the public for far too long and was an excellent addition to London's thriving South Bank," he said.