Bannockburn Riding for the Disabled Association near Stirling - a national centre for excellence - is facing a legal fight to stay open as its bitter row with landowner Bill Roddie escalates.
The centre has been embroiled in a dispute with millionaire property developer Mr Roddie since April when access to the site was closed off.
The charity has been at its home on Sauchieburn estate, near Kippen, for nearly 20 years and has its own stables, cafe and viewing balcony,
It was set up thanks to the generosity of the estate's previous owner, Guy Stafford, who paid to turn an old cowshed into what is now one of the most important centres of its kind in Scotland. The charity still has a number of years to run on its lease.
But now it seems certain the matter will end up in court after the charity received a letter from the landlord's lawyers telling it to vacate the premises.
Centre Manager Carol Simpson said: "The notice to quit is the first stage. He would have to go to court to get it enforced. We do not believe he has the right to do this but it is in the hands of our solicitors.
"We will defend our right to stay here and we're not going to leave on the basis of this notice. We're hoping that he sits down to talk to us instead before it gets to the stage where legal proceedings begin."
Mr Stafford died in 2006 and the estate was bought by Mr Roddie, a property developer who has a conviction for fraud.
Calls to Mr Roddie by The Herald through his company Spectrum Properties were not returned.
Previously, parents of centre-users recruited Stirling MSP Bruce Crawford - an old foe of Mr Roddie from right-to-roam rows - to their cause and he called for the landlord to act in a reasonable manner and discuss how the current impasse can be overcome.