Acadia Healthcare Company, which operates psychiatric hospitals, treatment centres and outpatient clinics in the US, has bought the group's 322 facilities, including the well-known clinic in Roehampton in south-west London.

Acadia will pay £1.28bn ($1.88 billion) in cash and issue 5.36m shares — worth about £230m — to Priory's owners, the private equity group Advent International.