Further delays to the Elizabeth Line seem “inevitable” in the face of coronavirus, the Mayor of London has said.

It comes as Crossrail bosses vowed to keep construction sites open where possible – but halt non-essential work on the project.

The long-awaited line will link Reading, Essex, Heathrow and south east London to the city centre – and increasing the capital’s rail capacity by 10 per cent.

Crossrail was originally due to open in December 2018 and cost £14.8 billion – but the timescale and price tag have since spiralled.

The central section of the line is now expected to start running in summer next year, with overall costs up to £18.25 billion.

Now bosses say non-essential work at its sites will stop, as they prioritise the health of workers.

But remote jobs will continue – a large part of the outstanding work is testing the technology used to control the line, which can happen off-site.

Sadiq Khan said yesterday (Thursday) he was “not sure” what effect the virus would have on the cost or opening date of the line.

Speaking at Mayor’s Question Time, he said: “Clearly there’ll be an impact.

“If I’m saying only essential workers should go to work, if I’m saying actually the best way to prevent spreading this virus is to stay at home unless you have to work, that has an impact.

“The Crossrail team will do what they can to work remotely where they can – but some of the things you need to be physically there to do, so I think it’s inevitable.”

Mr Khan said there would be “huge knock on consequences” for the cost of this and other projects.

He added: “To be fair to the Prime Minister – and it’s important I am fair to him – he has said he’s keen to make sure money is no object.

“We’ve got to take him at his word on that and he’s right to do so.”

Crossrail chief executive Mark Wild yesterday stressed that essential work on the line will continue as far as possible.

He said: “With immediate effect this week those who can work from home will do so.

“Essential and business critical work will continue across the Crossrail programme, but our priority is to keep our people safe and limit movement across our sites.

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

“We are doing everything we can to support our contractors during this difficult and challenging time and we will do what we can to keep individual sites open and productive as best as we can.”

Liberal Democrat London Assembly member Caroline Pidgeon – who raised the impact of coronavirus on Crossrail with the Mayor – said the prospect of more delays was “painful news”.

She said: “I believe the Mayor is right to admit that it is now inevitable there will be further delays to Crossrail’s completion, especially after the news that non-essential work has been halted.

“These additional delays will create huge problems in terms of rising construction costs as well as lost fare and commercial revenue.

“The consequences of this further delay should not become a burden that falls solely on London and Government support will be needed.”