British Prime Minister Boris Johnson ordered a new national lockdown in England on Oct. 31, amid a surge in coronavirus cases across Europe. (Video: Reuters)

LONDON — Prime Minister Boris Johnson announced a second national lockdown on Saturday as his scientific advisers warned that surging coronavirus infections could overwhelm British hospitals in six weeks.

As Britain passed the milestone of 1 million coronavirus cases, Johnson spoke at a gloomy news conference, saying he had hoped to avoid another sweeping lockdown but was confronted with stark data showing the virus was spreading rapidly.