A mental health charity has been told it must leave its market garden and coffee shop premises in the grounds of Hillsborough Castle.
Sixteen people with learning difficulties are employed at the centre - in a corner of the Hillsborough estate -run by Praxis.
The charity was given the use of the site nine years ago but was told of the NIO’s decision last year.
Praxis told the BBC it had invested £400,000 in improvements since moving to the site.
William McAllister from Praxis said: “To date, there has been no offer of compensation and no clear indication at all that we are in fact going to be compensated for all of the work that we have done in Hillsborough Castle.
“But we hold out hope that there will be some opportunity for us to properly negotiate with the Northern Ireland Office.”
People with special needs travel from across Northern Ireland to work there.
Centre manager Vanessa Coulter said: “It gives people a purpose, you know? People that have been in hospital for years, that have no confidence, no assertiveness skills, this is fundamental to how they develop as an adult with learning disability.
“It really is gutting. I can’t believe that it’s come to this.”
In a statement, the NIO said: “The NIO believes Praxis has had sufficient time to identify new premises to move to, and to prepare its clients for the move,” it said.
The castle’s transition to new management will being in April 2014, but many of the changes are not expected to take effect for two or three years.