A private company awarded a 10-year contract to save a failing GP surgery has mutually agreed to terminate its deal with the NHS after 16 months.
Circuit Lane Surgery in Reading was put in special measures in 2017 after a watchdog report said some patients were at significant risk of harm.
One Medical Group said it had "not been made aware of the challenges" the practice faced prior to taking it over.
Health bosses denied information had been "kept away" from the company.
The surgery was rated "inadequate" and placed in special measures by the Care Quality Commission (CQC) in April 2017.
In a statement, One Medical Group said the decision to end the contract was "independent" of the CQC's report.
It said the surgery's problems were "deep-rooted" for more than four years prior to it taking on the contract.
"One Medical Group was not made aware of the challenges the practice was facing, nor was it informed of the substantial backlog in clinical administration or lack of embedded processes," it said.
It said it had raised concerns early in the contract and had told Berkshire West Clinical Commissioning Group (CCG) that "should additional resources not be forthcoming, the contracts would not be sustainable".
"Unfortunately, despite the best efforts of the team and the CCG, the level of turnaround required has not been achievable within the funding envelope the CCG can afford," the statement added.
The CCG said: "The decision to find a new service provider was prompted in December 2017 when the surgery's current service provider, One Medical Group, and the CCG took a mutual decision to end the contract for Circuit Lane Surgery."
It added that the running of the surgery, which has 8,799 patients, had been transferred to the town's Western Elms Surgery on 1 April.