Not looking good in Italy either, 37,978 new cases and 636 dead.

One of the MPs, Lee Anderson, later tested positive for Covid-19, and on Sunday the prime minister was told to self-isolate by NHS Test and Trace.

In a video from No 10, Mr Johnson urged others to "follow the rules" if contacted by the system.

The PM's official spokesman insisted that Downing Street is "Covid-secure".

He said "social distancing did happen" but factors such as the length of the meeting were considered by Test and Trace.

Mr Johnson, who was admitted to intensive care with coronavirus seven months ago, spent about 35 minutes with Mr Anderson - who lost his sense of taste the day after the meeting.

The five other MPs self-isolating following the meeting with "Red Wall" Tories include:

• Heywood & Middleton MP Chris Clarkson
• South Ribble MP Katherine Fletcher
• Warrington South MP Andy Carter
• Great Grimsby MP Lia Nici
• Bassetlaw MP Brendan Clarke-Smith

Mr Johnson's spokesman declined to name the aides but suggested they were not Lee Cain or Dominic Cummings, who left Downing Street last week.