Some patients are receiving "unsafe" care in the NHS as the health service grapples with its worst ever winter pressures, medical colleges have warned.
The Academy of Medical Royal Colleges (AMRC) said that there was "insufficient resources and capacity" in the NHS as it faces a "real crisis".
In a statement on winter pressures in the health service, the AMRC said that unless politicians take action, the "winter crises" in the NHS will continue to worsen every year.
"Yet again, the NHS across the UK is facing a real crisis trying to cope with the winter pressures," according to the statement.
"The volume of activity means unacceptable waits for patients, delays in treatment or discharge and in some cases, unsafe care."
It adds: "Despite the fact the planning arrangements nationally and locally have generally been better than before and there has been clinical input at all levels, the problems have been worse than ever.
"But, the best planning in the world won't be effective if there are ultimately insufficient resources and capacity."
The AMRC called on health leaders to start planning for next winter.
The statement also sets out a number of solutions including more funding, properly integrated social care and "an honest debate about what kind of health and social care system people can reasonably expect and what it will cost to deliver that on a sustainable basis".