The UK has faced nearly 12,000 COVID-19 cases, including 580 deaths, with the Johnson government criticised from some corners over its alleged lackluster response during the initial outbreak period.

British Prime Minister Boris Johnson has tested positive for COVID-19, experiencing mild symptoms of infection on Thursday. UK Health Secretary Matt Hancock Tests Positive for Coronavirus.

In a tweet, the PM wrote that he was self-isolating, but promised that he would "continue to lead the government's response via video-conference as we fight the virus."

"I've developed mild symptoms of the coronavirus, that is to say, a temperature and a persistent cough, and on the advice of the chief medical officer I've taken a test. That has come out positive," Johnson explained in a video accompanying his tweet.

Johnson praised the National Health Service, police, social care workers, teachers and others for an "amazing national effort" in responding to the COVID-19 pandemic, and thanked the 600,000 people who've volunteered to assist.

"I want to thank everybody who's working to keep our country through this epidemic, and we will get through it. And the way we're going to get through it is of course by applying the measures that you have heard so much about," the prime minister said.

Number 10 moved to shut schools, shops, and to introduce restrictions on people leaving their homes after ruling that previous government warnings did not lead to a sufficient reduction in "unnecessary social interaction." The Johnson government has received criticism over perceived delays in taking action to fight the outbreak, and its laissez-faire 'herd immunity' approach to the virus, which it has since corrected.