Socialized medicine did not, as some predicted, collapse during COVID-19. Britain’s National Health Service was stretched to the limit but never overwhelmed. It’s the current phase of the pandemic that’s proving to be the bigger stress test.

The system is facing gargantuan backlogs across all areas, with the number of people waiting for treatment approaching 6 million. Patients suffering crippling arthritis must wait years for hip replacements or ankle surgeries in some cases. Hospitals are already at peak winter bed occupancy levels. Referrals for cancer screening have dropped worryingly. Burnout rates among Britain’s doctors and nurses have reached emergency levels. And don’t even mention the flu.

So how did the U.K. make it through the past 20 months of COVID-19? One key element needs to be acknowledged: the private sector’s role in delivering publicly funded care.