Plans to slash long waits for NHS treatment and cancer care by 2025 are in serious jeopardy, a damning report has concluded.
A report by the National Audit Office (NAO) suggested key NHS targets have been impacted by inflationary pressures, "significant" workforce shortages and productivity problems, and a reliance on GPs to absorb hospital work.
NHS England outlined a recovery plan after COVID-19 to reduce the backlog for patients including people battling cancer - but this is now at "serious risk", according to the NAO - the UK's independent spending watchdog.
Funding earmarked by the government to help the health service recover is not in line with inflation, the report warned.
The NHS England plan expected services to return to pre-pandemic levels of activity by early 2022/2023 - and hoped around 30% more treatments could be offered by 2024/25.
But increasing activity to these levels would be a "historic feat" and require "a rate of growth not seen in recent times".
The NHS is currently working at 96% of pre-pandemic levels.
Health bosses hoped that by March next year, the number of patients waiting more than two months for an urgent cancer care referral would return to pre-pandemic levels.
They set a target of March 2025 to eliminate elective care waits of more than a year.
But even if progress is made, people could still face long waits, the NAO report found.
To help achieve its targets, NHS England wants GPs to handle many cases previously dealt with by hospital doctors, the report said.
Instead of referring some patients to specialists, they are managed by GPs who receive guidance from hospital doctors.
NHS England believes this could avoid a total of 1.7 million outpatient appointments in 2022/23 - 1.1 million more than in 2019/2020.
But even taking this into account, the NHS needs to deliver an extra 7% average annual increase in activity, the NAO said.
Meanwhile, new community diagnostic centres have performed 1.8 million tests between July 2021 and September this year - but would need to conduct an extra 1.9 million texts to hit the diagnostic target set for March 2023, the NAO said.
Attempts to cut down on hospital follow-up appointments had caused concern among some clinicians and managers - due to fears for patient safety.
NHS England has set a target for a minimum 25% reduction in outpatient follow-up appointments by March 2023.
But just five out of 42 regional health organisations believe this is achievable.
Productivity slump is a 'serious problem'
NHS productivity was 16% less in 2021 compared to last year - described as a "major problem" by the NAO.
On average, staff are not carrying out as many procedures as before, due to increased sickness, less willingness to work paid or unpaid overtime, and the redeployment of staff between teams.
Productivity was also affected by COVID-19 infection control measures impacting operating theatre capacity and cancellations, together with a "reduced management focus by NHS trusts and NHS England on cost control and operational rigour".
Head of the NAO, Gareth Davies, said: "There are significant risks to the delivery of the plan to reduce long waits for elective and cancer care services by 2025."
The NHS needs to be "agile" in responding to the outcomes of different initiatives in the recovery programme, he added.
But a health services spokeswoman insisted the NHS was "on track" to deliver on its next recovery milestones after "virtually eliminating two-year waits for care and reducing 18-month waits by almost 60% in a year".
"Staff have achieved this despite higher staff absences, more COVID-19 patients in hospital this summer than the last two combined, reduced hospital capacity caused by social care issues discharging patients back into the community, and increased demand on urgent and emergency care services," she said.
It comes as the Royal College of Nursing last week announced its first strike in its 106-year history.
Prime Minister Rishi Sunak responded by saying the pay rise unions were asking for was "not affordable".