LONDON >> Thousands of ambulance workers in England and Wales went on strike Wednesday, walking out on their shifts and joining picket lines to demand pay increases and better working conditions in the largest labor unrest to hit Britain’s emergency services in decades.

The walkout, an effort by three unions that was expected to include over 20,000 workers, is the latest labor strike across numerous industries in recent weeks in Britain as a mounting cost-of-living crisis, spurred by double-digit inflation, grips the country. On Tuesday, nurses went on strike over pay that has not kept up with inflation, and rail workers and border control workers are scheduled to do the same this week.

In the ambulance services, workers have raised alarms about record delays for patients seeking emergency treatment, and paramedics have pointed to staffing shortages and burnout, as well as fears of arriving too late to help some callers.

Those issues have been exacerbated by entrenched problems within the National Health Service, where a high level of staffing vacancies has led to backlogs and long waits in hospital emergency rooms. Health workers are exhausted after working under highly stressful conditions during the pandemic, which also put their own lives at risk, and amid years of austerity measures that hollowed out public services after the 2009 financial crisis.

“We just cannot deal with the volume of calls,” said Antonia Gosnell, 53, who has worked as a paramedic for 33 years and was on a picket line in South London on Wednesday afternoon. “They all came out clapping for us during the pandemic, and now there’s nobody here to listen to what we want.”

Throughout the day, the ambulance services were prioritizing the most critical cases. Before the walkout, some hospitals asked people to arrange their own transportation to hospitals, including pregnant women going into labor. Patients needing nonurgent care were advised to look elsewhere for advice, including by telephone or from general practitioners or pharmacists.

With Christmas and end-of-year celebrations underway, health leaders urged people to avoid risky behavior on a day when services would be stretched. “Don’t get so drunk that you end up with an unnecessary visit to A&E,” Stephen Powis, the NHS medical director for England, said in a BBC interview, referring to the accident and emergency departments at hospitals.

The health service’s management said before the strike that there was “deep worry” about potential harm to patients at a time when the service was already under intense pressure.