Matt Hancock has been told to self-isolate for the second time after coming into contact with someone who has tested positive for coronavirus.
The Health Secretary said he had been “pinged” by the NHS test and trace app after he led a press conference from Downing Street on Monday.
He said he will now work from home until Sunday, and urged others to do the same if they are contacted after an encounter with someone who has the virus.
"This self-isolation is perhaps the most important part of all the social distancing because I know from the app that I've been in close contact with somebody who's tested positive, and this is how we break the chains of transmission,” Mr Hancock said in a video posted online.
"I've got to work from home for the next six days and together, by doing this, by following this and all the other panoply of rules that we've had to put in place, we can get through this and beat this virus."
The Health Secretary also underwent a period of self-isolation after testing positive for Covid-19 in July, at the same time as Boris Johnson had the virus.
Mr Hancock experienced mild symptoms, while the Prime Minister was hospitalised.
George Osborne, the former Chancellor of the Exchequer and current editor of the Evening Standard newspaper, said it was a “peculiarly British trait” that Mr Hancock had not been offered a vaccine, but “millions of health workers” had.
Responding, Mr Johnson’s official spokesman said: "We don't think it's right that the PM or other members of Cabinet take the vaccine in place of somebody who is at higher clinical risk."