Mark Wild told a Transport for London board meeting: “I can’t see how this job can be delivered in calendar year 19 – I don’t actually know when it will be delivered after that – but we are narrowing in (on a date) and it won’t be long before it starts to come into focus.”

He had earlier said that morale among the workforce is low, but that his new senior management team is working to “put the project back on its feet”.

Two critical paths for delivering Crossrail remain, Mark added; the dynamic testing of trains and completion of stations. One test train started running to a timetable between Abbey Wood and Paddington on 14 January and its stopping accuracy at platforms is said to be very good.

There remains “many, many weeks ahead of testing ahead of us,” he added. In three weeks’ time a second train will be put into the tunnel to test the signalling, before four trains are run.

But what is less certain is when the stations will be ready, he added. There is currently a “very large marching army” carrying out civil engineering, finishes and installations of escalators at nine central stations.

Each week, £30M is spent on Crossrail and while there are between six and seven thousand people working on the scheme, productivity is low. But Mark Wild also promised that Crossrail will, when opened, be “the world’s greatest metro railway”.

London’s Mayor Sadiq Khan thanked Mark Wild for his “candour and honesty” and said the quality and quantity of information provided to him is much improved since the new management team took over.

London Assembly Transport Committee chair Caroline Pidgeon said of the delay: “It’s not exactly a surprise but nevertheless disappointing to have confirmation that Crossrail is unlikely to open this year.

“It’s costing £30M a week to keep the project going and we still have no idea what the final bill will be for Londoners.”

She added that Crossrail will provide a much needed service to passengers and everyone is looking forward to its opening. “However, Transport for London and Crossrail must get a grip on the situation. Time is ticking and the cost is escalating.”

The London Chamber of Commerce & Industry’ transport policy manager Simon Dishman said: “Businesses need clarity on the actual delivery date, as it is key to their planning and preparation.

He added: “Businesses will also be concerned if the recent additional funding announcement for Crossrail impacts on the Crossrail 2 project. Let’s be clear that Crossrail 2 is also not a ‘nice to have’, but an essential infrastructure project for the future of London.”

(Photograph: Crossrail/TfL)