The National Gallery and Trafalgar Square are seen with a few visitors in London, Britain, on March 17.. Han Yan/Xinhua via ZUMA Wire

London could go into lockdown as early as Friday afternoon in an attempt to slow the spread of the coronavirus, according to reports in multiple UK news outlets.

Multiple UK government sources told CNN that conversations had taken place inside Downing Street looking at restricting travel in and out of the city, shutting parts of London's public transport and how these measures would be enforced.

Downing Street declined to comment on specifics or timing, but would not rule out any of the above measures put to them by CNN, repeating its position that the government will do all that is necessary to protect public health.

Pressed on the lockdown rumours in his daily coronavirus press briefing, Prime Minister Boris Johnson said: “We live in land of liberty ... and it's one of the great features of our lives we don't tend to impose those sorts of restrictions on people in this country, but I have to tell you we will rule nothing out and we will certainly wish to consider bringing forward further and faster measures where that is necessary."

The sources said that if such drastic measures were introduced, then Londoners would be given plenty of time to take any personal measures necessary ahead of the lockdown period.

Sources close to the Mayor of London's office told CNN that it didn't know anything at the moment, explaining that they had not been privy to any government thinking.

Johnson has repeated this week that London is ahead of the rest of the country in terms of the virus spreading and comments from Scotland's first minister, Nicola Sturgeon, that London could see tougher measures than the rest of the UK prompted fears of lockdown.

Right now, multiple sources close to the Prime Minister say they don't expect an announcement to be made imminently.

However, the regularity with which they are reminding us that the situation is developing faster than initially expected means that Londoners might be wise to keep an eye on the news in the coming days.

Watch: Brits blame UK government as coronavirus fears rise