Parliament could shut its doors for months under emergency government plans to tackle the spread of the coronavirus.
It follows the UK's biggest day-on-day increase in cases, with 87 people now confirmed to have the disease.
MPs on the Health and Social Care Committee committee are due to question England's chief medical officer Professor Chris Whitty on Thursday as to how well prepared the UK is to deal with the impact of a possible global pandemic.
Downing Street has confirmed that Boris Johnson is in talks with the parliamentary authorities about a possible shutdown if the outbreak continues to get worse.
One option is for parliament's Easter recess, due to start on March 31, to be brought forward. Another is for MPs and peers not to return after Easter, with the Commons and Lords suspended until September.
Other coronavirus developments:
- British beleaguered regional airline Flybe collapsed on Thursday, blaming coronavirus for its final demise
- Italy shut down all schools and universities and banned fans from sporting events after 3,089 people tested positive and 107 have died - the largest number of deaths outside China
- Eleven people have now died from coronavirus in the US, as California declared a state of emergency with 53 cases
- Some passengers on the Grand Princess cruise ship have been quarantined at sea off the Mexico coast after a group of patients in California who had been on the ship contracted the virus
- Australia has banned foreign arrivals from South Korea to slow the spread as it recorded its second illness
- In Iran, 77 people have died, including Iran's former ambassador to the Vatican
- In China, deaths and cases have lowered substantially. 31 people died on Thursday - seven fewer than the day before - and 139 were infected
Sky News has learned that Professor Whitty briefed the Commons Speaker Sir Lindsay Hoyle on Monday about the risks of coronavirus in the Palace of Westminster.
Commons Leader Jacob Rees-Mogg is certain to be quizzed about a potential shutdown of Parliament when he gives his regular Thursday morning statement to MPs on next week's Commons business.
And it is understood that the commissions of both Houses, made up of some of parliament's most senior MPs and peers, will discuss plans including suspending the Lords and Commons, when they meet next Monday.
Sir Lindsay, who succeeded John Bercow as Speaker last October, is said to be concerned about the spread of coronavirus, not only for the staff working in parliament, but also because the Palace of Westminster is a major tourist attraction.
Sir Lindsay's office has confirmed that he had held talks with Professor Whitty and is being kept updated by the chief medical officer's team and the Clerk of the Commons.
The possibility of a shutdown, which would be the first since parliament was bombed in the Second World War, emerged after the prime minister hinted to MPs that an announcement was imminent.
Mr Johnson said the chief medical officer, chief scientific adviser and Health Secretary Matt Hancock would be setting out the government's plans for dealing with "large gatherings" such as in parliament, in the next 48 hours.
"We are still at the containment stage," said the PM. "When we come to the delay phase you'll be hearing a lot more detail about what we propose to do about large gatherings and places such as parliament."
Later, a spokesman for the prime minister said: "Discussions are already taking place with parliamentary authorities and scientific and medical advisers.
"I'm sure parliament will be led by the advice of the experts in terms of taking the steps it needs in order to protect the people who work there."
A parliamentary spokesman added: "We are monitoring the situation closely and continue to work with the Department for Health and Public Health England.
"We have taken a range of precautionary measures including placing information posters across the parliamentary estate encouraging thorough hand-washing.
"We have been reassured by Public Health England that the steps we are taking to reduce the risk of transmission are proportionate and reasonable."
Mr Johnson's hint came in response to a question during PMQs from SNP MP Carol Monaghan, who said: "Every week 650 of us come here from every part of the UK, spend several days operating in close proximity and meeting people from all over the world, and we then return to our constituencies, potentially becoming the very vectors that we are trying to shut down.
"Parliament must stay open, but what plans does the prime minister have to utilise systems such as conference calls and electronic voting to ensure that we do not become part of the problem?"
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In the House of Lords, where the average age of peers is 70, fears have also been expressed for the health and wellbeing of elderly members, most of whom are in the age group worst-affected by the virus.
The leader of the Liberal Democrats peers, Lord Newby, said there were older peers with health issues who were considering not coming into the Lords, where peers' daily allowance is rising by an inflation-busting 3.1% to £323 a day in April.
"At this moment I don't think they are running to the hills but if there are more cases in London and they rose significantly then perhaps this could happen but I'm not aware of anybody taking that step yet," said Lord Newby.
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