Patients faced canceled treatments after thousands of British doctors walked off the job on Wednesday, the start of a six-day strike over pay that was set to be the longest in the history of the state-funded National Health Service.

Managers said tens of thousands of appointments and operations will be postponed because of the walkout across England by junior doctors, those in the first years of their careers. The doctors, who form the backbone of hospital and clinic care, plan to stay off the job until 7 a.m. on Tuesday.

Senior doctors and other medics have been drafted to cover for emergency services, critical care and maternity services.

Julian Hartley, chief executive of heath care managers’ organization NHS Providers, said the strike came at one of the toughest times of the year for the health service, “immediately after the Christmas and New Year period because of the pressures the demands, and of course we’ve got flu, we’ve got COVID.

“So there’s going to be an impact on patients that will be significant,” he said.

Britain has endured a year of rolling strikes across the health sector as staff sought pay rises to offset the soaring cost of living. Unions say wages, especially in the public sector, have fallen in real terms over the past decade, and double-digit inflation in late 2022 and early 2023, fueled by sharply rising food and energy prices, left many workers struggling to pay bills.

The union says newly qualified doctors earn 15.53 pounds ($19.37) an hour — the U.K. minimum wage is just over 10 pounds an hour — though salaries rise rapidly after the first year.