A millionaire businessman has pulled the plug on a £15m deal to keep a collection of 17th Century paintings in the home of the Bishop of Durham.
In March, investment banker Jonathan Ruffer gifted the cash to a campaign to save 12 works by Spanish artist Francisco Zurbaran.
But now Mr Ruffer claims conditions have been put on the deal by Church Commissioners, who own the paintings.
The future of the paintings, which hang in Auckland Castle, is now in doubt.
Associated plans to develop Auckland Castle as a major tourist attraction are also in doubt after Mr Ruffer's decision.
In a statement he said: "On 31 March 2011 the Church Commissioners and I announced that I would purchase a series of 12 paintings by the artist Francisco de Zurbaran, which have hung since 1756 at Auckland Castle, for the price of £15m to be held in a new charitable trust, the Zurbaran Trust.
"This unconditional contract was confirmed by the asset committee of the Church Commissioners in March of this year.
"I have established that the first estates commissioner and the chief executive of the Church Commissioners have added conditions to the sale of the Zurbarans, conditions which are insurmountable.
"I have no option but to withdraw my offer. This is a great sadness and an embarrassment.
"The entire £15m which I have pledged will be used for the people of the north east of England within the Zurbaran Trust, which will continue to function.
"I will do everything that I can to ensure that the pictures remain at Auckland Castle."
A spokesman for the Church Commissioners said: "Mr Ruffer's original offer was an extremely generous one that not only would secure the future of the paintings in the North East, but also open up some exciting possibilities for heritage protection, regeneration and employment creation.
"We remain committed to helping to provide the best possible solution for Auckland Castle and its paintings, one that will benefit the region, town, its residents and the Church."
The Bishop of Durham has urged the two sides to "look afresh" at the deal.
The Right Reverend Justin Welby, said: "The disappointing news of the breakdown of the current arrangements for Mr Jonathan Ruffer to buy the Zurbaran paintings reopens the questions about the future of the paintings and of Auckland Castle.
"Everything possible still needs to be done to ensure that the paintings remain on the site designed for them, and that Auckland Castle is developed as a major cultural and tourist resource for the area.
"I ask Mr Ruffer and the Church Commissioners to look afresh at what can be done, bearing in mind that the North East has an extraordinary Christian heritage."