Boris Johnson has insisted he will continue to lead the Government’s pandemic response as he self-isolates after meeting an MP who tested positive for Covid-19.

The Prime Minister had been planning to start the week by relaunching his premiership after days of infighting which led to the exit of his top adviser Dominic Cummings and communications director Lee Cain.

Mr Johnson, who was admitted to intensive care with coronavirus in April, was notified by NHS Test and Trace on Sunday that he must self-isolate and remain at Number 10 for 14 days.

In a video message posted on Twitter on Monday morning, Mr Johnson said he would continue to “lead on our response to the virus & our plans to #BuildBackBetter”.

He said he was “in good health” and that he has “no symptoms” after the meeting with Tory MP Lee Anderson.

Mr Johnson said he would have “plenty more to say by Zoom and other means of electronic communication” as he looks to move on from a tumultuous past week at the top of Government.

At least four other Conservative MPs who were at the meeting – Katherine Fletcher (South Ribble), Andy Carter (Warrington South), Lia Nici (Great Grimsby) and Brendan Clarke-Smith (Bassetlaw) – are also now self-isolating.

Jacob Young, the MP for Redcar, is self-isolating after having been in contact with Mr Anderson – although he was not at the meeting – while Basingstoke MP Maria Miller has said she is self-isolating after having been contacted by Test and Trace.

On Sunday night, Downing Street said Mr Johnson would present a committed policy launch on social justice, “levelling up” and coronavirus over the coming weeks following the sudden exit from No 10 of Mr Cummings and Mr Cain.

No 10 said the “critical announcements” due over the coming weeks would send a “clear signal of his ongoing ambitions for the United Kingdom”.

It is also a pivotal week for Brexit, as negotiations with the EU reach their final phase.

Health Secretary Matt Hancock will host a No 10 press conference on Monday evening which Mr Johnson had been expected to lead.

Mr Johnson was advised to self-isolate after attending a 35-minute meeting with a small group of MPs in Downing Street on Thursday morning.

It included Mr Anderson, MP, for Ashfield, Nottinghamshire, who said he lost his sense of taste on Friday and, after being tested on Saturday, received a positive result on Sunday morning.

The two men were not wearing face coverings and did not appear to be two metres apart in a photo taken at Downing Street which Mr Anderson posted on Facebook.

Asked if Mr Johnson would be able to take part remotely in Commons events, such as Prime Minister’s Question Time on Wednesday, a Number 10 spokesperson said: “I think that’s what they are trying to work through.”

In his Twitter message, the Prime Minister said: “Hi folks, the good news is that NHS Test and Trace is working ever-more efficiently, but the bad news is that they’ve pinged me and I’ve got to self isolate because someone I was in contact with a few days ago has developed Covid.

“It doesn’t matter that we were all doing social distancing, it doesn’t matter that I’m fit as a butcher’s dog, feel great – so many people do in my circumstances.

“And actually it doesn’t matter that I’ve had the disease and I’m bursting with antibodies. We’ve got to interrupt the spread of the disease and one of the ways we can do that now is by self-isolating for 14 days when contacted by Test and Trace.”

Mr Hancock said Boris Johnson would be able to work fully from home and was “very sprightly”.

He told BBC Breakfast: “I’d say probably the majority of my meetings with the Prime Minister are over video conference – of course I see him as well – and you can be really effective that way.”

Asked why Mr Johnson was not considered to have immunity having already contracted the virus before, Mr Hancock told BBC Radio 4’s Today programme: “The answer is because some people do get it again.”

He said everyone had to obey social distancing rules because there was not yet the “rigorous evidence we need on how likely people are to catch it twice”.