LONDON — British Health Secretary Matt Hancock is quarantining himself after receiving an alert from the country’s test and trace app saying that he has recently been in close contact with someone who has tested positive for COVID-19.

In a video posted on Twitter, Hancock said he has been pinged by the National Health Service’s coronavirus app and that he will be self-isolating at home until Sunday.

Hancock, who contracted the virus last spring, says self-isolation is “perhaps the most important part” of all the social distancing measures in place to break chains of transmission.

Britain is facing an acute resurgence of the coronavirus that has seen lockdown measures reimposed across the country. The Office for National Statistics said separately that one in eight people in England have had the virus, the highest rate among the four U.K. nations. Britain has seen over 90,000 confirmed deaths, the most in Europe.