Nurses, postal workers and railway employees are all walking out this month in the U.K.'s largest series of labor actions in more than a decade. It's a major challenge to Prime Minister Rishi Sunak.

The World War II veteran gained fame by raising funds for the U.K.'s National Health Service by walking sponsored laps in his garden. His family says he contracted COVID-19.

A new and more transmissible variant is threatening to overwhelm England's health care system, the prime minister said.