Boris Johnson is in self isolation after coming into contact with someone with coronavirus.
The Prime Minister was reportedly contacted by NHS Test and Trace and told that he needs to self isolate as a contact of someone who has tested positive for Covid-19.
Mr Johnson is not believed to have any symptoms of the virus.
Downing Street confirmed that the Prime Minister had been told to self isolate.
A No 10 spokesman said: "The Prime Minister has today been notified by NHS Test and Trace that he is required to self-isolate as a contact of someone who has tested positive for Covid-19.
"The Prime Minister will follow the rules and is self-isolating.
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"He will carry on working from Downing Street, including on leading the Government's response to the coronavirus pandemic.
"The PM is well and does not have any symptoms of Covid-19."
BBC journalist Laura Kuenssberg confirmed the news and said on Twitter: "The PM is self-isolating after being in a meeting with an MP, Lee Anderson, who developed Covid - night before what was meant to be big relaunch week after torrid soap opera of last few days."
Last week two big figures left Downing Street in the form of Dominic Cummings and Lee Cain.
Boris Johnson's top adviser Dominic Cummings has left his post with immediate effect.
A civil war broke out at Number 10 last week with Mr Cummings was said to be angry that his ally, Downing Street communications boss Lee Cain had not been given the job of Boris Johnson's Chief of Staff, leading him to quit government himself.
Mr Cummings was pictured leaving Number 10 with a large box of items on Friday.
