State-owned lender Royal Bank of Scotland (RBS) has sold its majority stake in care homes operator the Priory Group.Private equity firm Advent International is buying the group, best known for providing rehabilitation facilities to celebrities such as Amy Winehouse and Pete Doherty, for an enterprise value of up to £925m.After the settlement of outstanding debt, RBS expects to receive gross equity proceeds of up to £133m in cash from the sale of its minority equity stake in the Priory Group.The sale of this legacy private equity asset marks further progress in the execution of the asset reduction element of RBS's strategic plan announced in February 2009, the statement said. The sale remains subject to certain conditions and is expected to complete in the first quarter of 2011. The group's stake in the rehabilitation clinics group has been on the chopping block for several months after plans for a £1bn-plus flotation were binned last year.The Priory Group was founded in 1980 by an American healthcare company. The group specialises in the provision of acute mental health care, secure and step down services, specialist education, complex care and neuro-rehabilitation services, fostering and care homes.