Construction work on all Crossrail sites has been halted today, following new government instructions telling people to stay at home.

Prime Minister Boris Johnson said last night that only essential staff should be travelling to work.

And today, the Mayor of London Sadiq Khan told ITV’s Good Morning Britain he believes construction workers should no longer be on sites, due to the risk from the virus.

His comments came as commuters again complained of busy Tube trains this morning – which put key workers such as NHS staff and police at greater risk from the virus.

Now Crossrail has announced that all construction sites will shut down as soon as is safely possible.

This will mean further delays to the long-awaited rail link.

Once completed, Crossrail will connect Reading, Heathrow and Essex to central and south east London, and increase rail capacity in the capital by 10 per cent.

Originally set to open in December 2018, the central section of the Elizabeth line is currently scheduled to start running in summer next year.

Costs have also risen, from £14.8 billion to as much as £18.25 billion now – while revenue from predicted ticket sales has been lost because of delays.

TfL boss Mike Brown said the Government and the Mayor had given “clear instructions” that only essential workers should be travelling.

He said: “In line with this, TfL and Crossrail will be bringing all project sites to a temporary Safe Stop unless they need to continue for operational safety reasons.

“This means that work on all such projects will be temporarily suspended as soon as it is safe to do so. Essential maintenance of the transport network will of course continue.

“This is being done to ensure the safety of our construction and project teams and also to further reduce the number of people travelling on the public transport network.”

The transport commissioner said TfL would work with contractors to ensure “consideration will be given to the impact on workers, particularly those who are on low incomes”.

But it is not yet clear what pay and support Crossrail workers will receive.

Last week, Sadiq Khan said further delays to the project seemed “inevitable” and chief executive Mark Wild announced all staff would work from home where possible.

Much of the outstanding work on the project involves testing software that will be used to run trains – and this can still be carried out remotely.

Crossrail had hoped to keep construction sites open where possible – but today the chief executive said those plans had to change.

Mr Wild said: “While we are doing everything we safely can to keep the Crossrail programme on track, covid-19 will have an impact – it’s too early to tell what that impact will be.”

The Government has now (March 23) ordered everyone to stay at home unless absolutely necessary to fight the spread of coronavirus. You can find the latest guidance here. Advice on the virus from Public Health England is available here.