It will be months before the NHS is able to fully restart services in the aftermath of the coronavirus outbreak, health leaders have warned.
Experts from the Health Foundation, the King's Fund and the Nuffield Trust will tell MPs on Thursday of the significant challenges facing the health service as it tries to create a "new normal".
It comes as NHS waiting list data is due to be published - which is expected to show the number of people waiting for treatment has swollen during the pandemic.
The waiting list for planned treatment stood at around 4.4 million before the Covid-19 outbreak but is now expected to be much higher.
A separate report from NHS Providers, which represents NHS organisations, warns there are challenges to ramping up care for people with non-Covid conditions while still caring for virus patients.
In a joint submission to the Commons Health and Social Care Committee, the three groups said the Government and health and care leaders should not underestimate the pandemic's impact on already exhausted NHS staff.
They warned that an information campaign will be needed to urge the public to overcome their fears and start using the NHS again, while preparations must also be made for a possible second peak of the virus - alongside the usual winter pressures such as seasonal flu.
The organisations also said more personal protective equipment (PPE) will be needed as non-Covid services resume, they also called for more space to be allocated so patients and staff can socially distance, and stressed a need for greater levels of testing.
These factors, together with the extra time needed for cleaning equipment and facilities, will "severely limit capacity for many months until the infection has been brought under control in the community," they warned.
The groups warned that the pandemic has exposed "pre-existing weaknesses" within the healthcare system - most obviously a long-term under-investment in health and care services and a "precarious" social care system.
"These issues will still need to be tackled alongside the backlog of demand," they warned.
Nigel Edwards, chief executive of Nuffield Trust, said: "With the virus still at large there is no easy route back to the way things were before in the NHS, and unfortunately that means people waiting much longer and some services being put on hold.
"Hospitals and a whole range of services provided in the community will have to be remodelled to control infection and keep people safe, by separating out coronavirus patients and testing constantly and quickly at every level.
"We must be honest that this will slow things down."
Jennifer Dixon, chief executive of the Health Foundation, added: "Getting services back up and running, taking account of likely future pressures from Covid-19, winter, and the backlog of ill health from delayed care will be a steep climb.
"But Covid-19 has also demonstrated how the health and care system can move fast, implement new technology and ways of working, and the deep commitment of NHS and care staff."
Richard Murray, chief executive of the King's Fund, said: "The health and care system is a complex web of inter-related services: when one part fails, patients and service users can easily fall between the gaps.
"All aspects of the health and care system will need to be back up and running if services are to return to any semblance of normality.
"In the case of social care, normality should not be the aim: the sector needs increased funding and fundamental reform."
The report from NHS Providers echoes some of these calls, saying there is a huge task in restarting the full range of NHS services while managing the threat from Covid-19.
It says trusts will still need to care for virus patients and keep enough capacity in the system in case there is a second wave of infection.
It warns of backlogs, increased new demand for mental health services due to the effects of Covid-19 - and the need to care for NHS staff who have experienced highly pressured "once in a career" circumstances.
New challenges include a lack of PPE and testing, shortages of key drugs and equipment, including anaesthetic drugs and kidney dialysis machines, and the need for staff to take leave they have deferred due to the outbreak.
"Given the scale of these challenges and constraints, it is already clear that NHS trusts will be unable to deliver all that is expected," the report warned.
"We must, therefore, have an open and honest debate about priorities."
The chief executive of NHS Providers, Chris Hopson, who is also giving evidence to the Health and Social Care Select Committee, said: "The NHS has performed extremely well through the first peak of the virus, but that’s just the first few laps of what we know will be a marathon.
"Only now is the scale of the challenge for the rest of the race coming into view.
"Trusts will do all they can to restart services as quickly as possible. They’ll seek to solve every problem they encounter as they’ve consistently done so far.
"They will build on the innovations they've developed over the last two months, like the 6,000 patient consultations a day now being delivered online, compared to 200 before the crisis.
He warned, however: "One key lesson from the pandemic so far is not to over-promise. We must recognise that the NHS cannot deliver all that is now being asked of it. Expectations are already way ahead of reality."
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