London: British Prime Minister Boris Johnson has tested positive for coronavirus and has been forced into isolation during the worsening emergency in the United Kingdom.

In a video posted to Twitter, Johnson, aged 55, said he had developed mild symptoms and was tested inside Downing Street by National Health Service staff on the advice of the country's chief medical officer.

Prime Minister Boris Johnson has tested positive for COVID-19. Credit:Getty

He vowed to continue leading Britain's response to the pandemic via teleconferencing, however the diagnosis will raise questions about the Prime Minister's contact over recent weeks with other key officials and cabinet ministers.

"I am working from home, I'm self-isolating and that's entirely the right thing to do but be in no doubt that I can continue, thanks to the wizardry of modern technology, to communicate with my top team to lead the fightback against coronavirus," he said.