It kept health workers form the frontline and meant NHS England had to pay out for lost earnings.
"The failure to update performers lists may have compromised patient safety in cases where practitioners should have been removed", the authors of the report said.
A botched £330m seven-year NHS contract with Capita to outsource back-office support for 39,000 Global Positioning System, dentists and opticians was today savaged by the United Kingdom government's spending watchdog over its "potential to seriously harm patients".
"This was the first time the NHS in England had ever centrally contracted these services", they said.
'We hope that lessons are learned from the report; NHS England, Capita and more importantly patients can not afford another fiasco on this scale'.
The National Audit Office outlined severe service failures that came about after Capita took over primary care support services and launched a transformation programme that aimed to cut costs for NHS England by 35% from the first year of the contract.
"The complexity of the support services being led by NHS England was not fully understood when the contract was signed", Capita added.
"As a result, both parties misjudged the scale and nature of the risk in outsourcing these services".
But the report said the service from Capita "has fallen a long way below an acceptable standard".
The report found that the impact on the delivery of primary care services had the potential to seriously harm patients, although no actual harm to patients has been identified.
Dr Richard Vautrey, chairman of the British Medical Association's GP committee, said it was asking NHS England how it planned to resolve the "shambles" of Capita running the primary care support services.
"It is deeply unsatisfactory that, two and a half years into the contract, NHS England and Capita have not yet reached the level of partnership working required to make a contract like this work effectively".
But Sir Amyas Morse, the head of the watchdog, added that value for money was "about more than just cost reduction".
While Capita's service provision "has improved, widespread failures are still being experienced", the NAO stressed, with seven "severe service failings" highlighted in February 2018.
Although the mistakes did not result in any harm, they will raise further concerns about the NHS's cancer screening.
Meg Hillier, Labour and Co-operative MP for Hackney South and Shoreditch, and chair of the Committee of Public Accounts, said that NHS England and Capita's service provision was "over ambitious [and] disruptive...and potentially put patients at risk of serious harm".
The auditors called for consideration as to whether elements of the contract should be taken back in-house.
An NHS England spokesman said the transition, "while not without its difficulties", had saved £60m which had been reinvested into front-line care, funding the equivalent of an extra 30,000 operations.
The report said Capita "acknowledges that it made performance issues worse" when it continued to close support offices in the summer of 2016 "even though it was aware" its customer service centre "was struggling to meet demand".
Capita accepted accountability for not meeting high standards of service previously, the spokesperson emphasised.
Girl killed during Newburgh storm identified
The unnamed girl died after she was unloading a auto alongside her mother before strong wind gusts pushed the tree on the vehicle. The 80-year-old woman was driving alone in a 2018 Hyundai during the powerful storm when a tree fell on top of her vehicle.
Aberdeen New Thai Investment Trust Plc (ANW.L) Moves 0.35%
Advancing issues outnumbered declining ones on the NYSE by a 2.30-to-1 ratio; on the Nasdaq , a 2.62-to-1 ratio favored advancers. Now the stock price is moving -30.27% off from the highest level of twelve months and +482.95% above from twelve months low.
FDA approves Amgen drug for prevention of migraines
Preventive medications may be an option for around eight million Americans suffering from migraine, Amgen said . Aimovig is one of a handful of preventive migraine drugs, with a handful also in front of the FDA for review.