The High Court has granted a trespass order against solicitor Brian O'Donnell over the Gorse Hill property in South Dublin.
Mr Justice Brian McGovern has told the solicitor, who owes Bank of Ireland more than €70m, that he must leave the property by 5pm tomorrow.
The judge said Mr O'Donnell and his wife Mary Patricia were "trespassers" who ordinarily live in the UK and "flew in" to "frustrate" the bank and receivers from taking possession of the house.
The court heard that Mr O'Donnell had called in the land league to "blockade" the €7m house in Killiney and "prevent" the repossession.
Brian O'Donnell has already indicated he intends to appeal the court's decision.
Mr O’Donnell and his wife, psychiatrist Mary Patricia, consented in an agreement with Bank of Ireland four years ago to vacate the property if the lender sought it as security on the pair’s debts.