Upgrade for Hillsborough Castle
The Northern Ireland Office (NIO) has spent £1.25 million upgrading Hillsborough Castle for visitors.
Management of the castle is being transferred to Historic Royal Palaces (HRP) along with a running cost of £1.5 million a year.
A mental health charity has been involved in a long-running battle against eviction from the complex. The High Court last month said Praxis must leave its cafe and market garden at the Co Down site.
An NIO spokeswoman said: "The £1.25 million represents additional investment in the castle which combined with significant investment by HRP will ultimately result in a much more impressive visitor attraction.
"This will hopefully attract significantly more visitors while at the same time generating a considerable saving for the taxpayer over the life of the contract."
Hillsborough Castle has been a royal residence and the home of the Northern Ireland Secretary since the 1970s.
The new arrangements will result in HRP being responsible for the running costs.
The HRP website said: " Our aim is to develop and re-present the Hillsborough Castle site; to help everyone explore the important historical role it has played; and to make the castle and its gardens widely accessible for future generations to share and enjoy.
"Our long-term plan for Hillsborough Castle and its beautiful gardens aims to open up the estate for the benefit of the whole community and give a richer experience to visitors exploring the castle and its history."
An Assembly motion last year called on the NIO to make the transfer conditional on Praxis being able to stay.
However, the department said the charity had had enough time to make alternative arrangements.
Seven staff and 16 people with learning difficulties worked at the centre.
An NIO spokeswoman said the High Court has ruled that Praxis must vacate the premises it occupies on the Walled Garden site at Hillsborough Castle by April 24.
"We are aware that Praxis is already taking steps to ensure that they do vacate by that date, but as far as we know they have not yet left the site."