FILE PHOTO: Britain's Prime Minister Boris Johnson leaves Downing Street to attend a cabinet meeting at the Foreign and Commonwealth Office (FCO) in London, Britain November 10, 2020. REUTERS

Boris Johnson has been forced to self-isolate in Downing Street after meeting an MP who later tested positive for Covid-19.

NHS test and trace had said factors including the length of the meeting meant Johnson should self-isolate as a precaution.

In a video posted to Twitter on Monday, Boris Johnson said: “It doesn’t matter that I’ve had the disease and I’m bursting with antibodies”. He urged others to “follow the rules” and self-isolate if contacted by the scheme.

On Thursday Mr. Johnson spent about 35 minutes with Tory MP Lee Anderson, who tested positive the next day.

Johnson was seen standing next to Lee Anderson, the MP for Ashfield in Nottinghamshire, inside Downing Street on Thursday.

The men appear to be less than 2 meters apart and neither is wearing a mask.

It comes as the government prepares a policy relaunch after fierce internal rows and departures from No 10.

Downing Street said a series of “critical announcements” would this week detail Mr Johnson’s “ambitions for the United Kingdom”.

He might carry out last-minute negotiations in a potentially crucial week for Brexit on Zoom.