Hinchingbrooke Hospital was re-inspected by the Care Quality Commission (CQC) days before the release of a critical report into the hospital and found to have improved.
The inspection was carried out on 2 January and the subsequent report saw the hospital trust rated as "requiring improvement" rather than "inadequate".
Circle announced its withdrawal from as the UK's first private provider to run an NHS hospital just hours before the CQC report was published on 9 January.
However, despite the improvement, the trust has not been removed from special measures, into which it was placed following the "inadequate" rating.
The trust remains rated as "inadequate" as to whether or not it is well-led.
Ffollowing the hospital's return to NHS control a new chairman of the trust running the hospital was appointed.
Currently outpatients and diagnostic imaging; maternity & gynaecology and critical care services at the hospital have an overall rating of good, as do most of the services for the criteria of being caring and responsive.
The CQC inspects both private hospitals and NHS hospitals, with the first private hospitals having been inspected in October 2014.
Professor Sir Mike Richards, chief inspector of hospitals at the CQC, said: "When we returned to inspect Hinchingbrooke Health Care NHS Trust we found a number of improvements had been made on the Apple Tree and Juniper Wards.
"We were pleased the trust had acted swiftly to make improvements to these wards and to safety in the emergency department. However, these changes need to be sustained and embedded.
"I am not recommending the trust comes out of special measures at this stage and our inspectors will return to check on what further improvements have been made at a later date.
"The trust is being supported by the Trust Development Authority (TDA) with regard to its programme of improvement and CQC is also in regular contact with the TDA as it continues its monitoring of the trust.
"The trust knows what it needs to do to make further improvements and ensure those already made are maintained."
Hisham Abdel-Rahman, chief executive officer of Hinchingbrooke Health Care NHS Trust said: "Today's report from the CQC recognises the ongoing hard work and effort of staff here at Hinchingbrooke to make sure we provide high quality and safe services for all our patients, day and night.
"I am pleased that our overall rating has improved and that over half of all the areas inspected are now rated as ‘good'.
"The services and areas which were inspected during this limited January inspection have all seen their ratings improve. Those areas which were not inspected, such as whether we were ‘well-led', continue to reflect their rating from last September.
"At the time of this inspection, we had completed around one-third of our action plan to address the CQC's concerns.
"We have now passed two-thirds of our milestones and have a firm plan in place to resolve all outstanding issues as soon as possible."
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