Hospitals are running out of space in corridors with a spike in flu cases plunging the NHS into winter chaos, senior doctors have warned.

On New Year's Eve patients were urged to only call 999 if their situation was “life-threatening” or extremely serious in a desperate bid to ease strain on overloaded paramedic crews.

Ambulance services warned they were under heavy pressure even before New Year’s Eve - traditionally their busiest night of the year - had begun.

And senior doctors said some Accident & Emergency (A&E) units had become so overcrowded that they had run out of corridor space for patients, amid waits of more than 12 hours.

NHS surveillance suggests flu cases have risen by 67 per cent in a week in England - meaning around 3.7 million people came down with such symptoms over the Christmas period.

The data held by Public Health England shows the flu season now underway across England, Scotland and Wales, with a significant increase in deaths in Scotland.

Health officials had already warned they were “more scared than we have ever been” about the risk of a heavy flu season, if Britain follows Australia in being hit by the worst flu season for almost two decades.