An ambulance is parked outside St Thomas' Hospital in London. Several British hospitals are canceling all but emergency appointments to deal with a surge in demand. (Isabel Infantes/AFP/Getty Images)

LONDON — Many hospitals in Britain are canceling all routine appointments and surgeries until February as they struggle to handle spikes in demand during the winter season. The cancellations could potentially affect tens of thousands of patients.

British Prime Minister Theresa May told Sky News on Wednesday that she recognizes that the cancellations are “disappointing” and “frustrating” for those affected. But she insisted that Britain's National Health Service is “better prepared for this winter than ever before.”

On Tuesday evening, officials at the National Health Service in England recommended that hospitals cancel non-urgent appointments and operations in January to free up space for the sickest patients. It’s estimated that this could affect 55,000 surgeries. Cancer surgeries and time-critical procedures should proceed as planned, officials said.

Several of Britain’s national newspapers featured the story on their front pages.

Britons are fiercely proud of their national health service, but it is not uncommon for hospitals to face significant strain during the winter months when they don’t have many spare beds and there is greater demand. Last year, the British Red Cross called the situation a “humanitarian crisis.”

The latest recommendations extend those made in December that non-urgent operations should be canceled in the first two weeks of January.

The NHS Providers, a trade association, said in a statement that many hospitals are dealing with “unprecedented demand,” because of an increase in “flu and respiratory illness, the impact of norovirus and — in some places — primary care, including GPs working at more than full stretch.”

Chris Hopson, chief executive of NHS Providers, said on Twitter that hospital leaders are “creating extra temporary capacity, calling in staff to work extra shifts, delaying non urgent work. But this still means that, in some places, waiting times and care under real pressure.”

He also noted that the situation is similar to that of last year. “NHS staff giving their all, once again. Current approach not sustainable long term . . . But we said that last year!” he tweeted.

Some health professionals also jumped on social media to discuss the situation. Richard Fawcett, an emergency physician at the University of North Midlands NHS Trust, apologized for the “3rd world conditions of the dept due to overcrowding.”

Stein Villiers, a nurse, asked when it became normal to care for patients in corridors and waiting rooms.

Chris Turner, a doctor, said that the current pressures were a “system fail.”