A report from the British Medical Association has found more than a million patients are set to face huge waits in emergency department in the upcoming months.
Last winter more than 23,000 patients across Yorkshire and Lincolnshire had to wait more than four hours to be seen in accident and emergency.
Now the NHS is braced for its "worst-ever" winter, with pressure on the service set to skyrocket.
The warning from the doctors union comes amid claims at least one patient has had to wait up to 20 hours to be seen at Lincoln County Hospital.
NHS chiefs at the hospital admit there have been long delays in the past few days caused by a sharp rise in the number of very poorly patients attending the casualty department combined with an outbreak of winter sickness.
The BMA is calling for health spending to be increased by at least 4.1% each year to get the NHS "back on a sustainable footing".