The full details on the London lockdown from Gordon Rayner, our political editor:

Downing Street has insisted there is “zero prospect” of people being banned from travelling in and out of London as it denied the capital would be put into “lockdown”.

The Prime Minister’s official spokesman said there was also no chance of the London Transport network being closed down.

Reports of households being restricted to one person leaving at a time are “not true”, the spokesman added.

On Wednesday Boris Johnson said he would rule nothing out when it came to restrictions on transport, fuelling speculation about a major clampdown this weekend.

But at a briefing for journalists in Downing Street, Mr Johnson’s spokesman moved to rule out some of the more extreme measures that were reported to be under consideration.

The spokesman said: “There are no plans to close down the transport network and there is zero prospect of any restriction being placed on travelling in or out of London. It is not happening.

“The Prime Minister and his advisers have set out the need for social distancing measures to limit the spread of the virus and to protect lives.

“What we are focused on is ensuring that as many people as possible take that advice and don’t unnecessarily put themselves in a position where they could spread coronavirus.”

The spokesman said any further guidance issued to Londoners would be likely to centre on avoiding pubs and restaurants and on increased home working.

London Transport has shut 40 Underground stations as part of a reduced service, which was done in consultation with the Department for Transport, but No10 insisted Tubes and buses would continue to run.

Asked if access to the transport system could be restricted to key workers, the spokesman said: “I have seen absolutely no suggestion that the Government is intending to restrict access to the transport system.”

The spokesman also played down suggestions that people could be fined for disobeying the Government advice - as France has started doing - saying the power to do so existed, but had only been introduced to prevent people leaving quarantine facilities at the start of the outbreak.

Asked about reports that families could be restricted to one person leaving the house at a time, the spokesman said: “That is not true.”

One Whitehall official went further, saying the Government would “never” lock down cities in the way that has happened in some European countries.

The same source said: “There isn’t going to come any point where border guards are stopping people coming in and out of London. That is not the sort of country we are.”