Crossrail, the new railway to link London and the South East, has been delayed again to summer 2022 and costs are expected to have increased by an additional £1.1 billion.
This follows an update as recently as July where it was announced that the central section of the new Elizabeth Line could not open in summer 2021.
The total cost for Crossrail is now estimated to be approximately £18.7bn.
Dr Alison Moore, chair of the London Assembly Transport Committee, described the latest delay as “extremely disappointing”.
Moore said: “The news will certainly frustrate Londoners again because people were expecting to use the line from December 2018.
“Londoners will accept that Covid-19 has played a significant role in this delay, and that the complexity of this project and the need to complete the work safely have meant it’s had to be pushed back yet again.
“Understandably, that won’t take away any disappointment or any concern that costs are escalating.
“Lessons must be learned from the way Crossrail officials originally planned for this major infrastructure project.
“Crossrail will be a fantastic asset to London once it is finally finished and the London Assembly Transport Committee will continue to keep a close watch on developments.”
Crossrail is planning to start operational testing, known as Trial Running, “at the earliest opportunity” in 2021.
From the start of Trial Running it will then take “a period of time”, which is currently undefined by Crossrail, to fully test the Elizabeth line before it can open for passenger service.
This includes a final phase known as Trial Operations involving people being invited onto trains and stations to test real-time service scenarios to ensure the readiness of the railway.
To help recover some of the lost time, Crossrail is undertaking a period of construction activity during August and September to complete the remaining construction works in the routeway for Trial Running.
Mark Wild, Crossrail chief executive, said: “Our focus remains on opening the Elizabeth Line as soon as possible.
“Now more than ever Londoners are relying on the capacity and connectivity that the Elizabeth Line will bring, and we are doing everything possible to deliver the railway as safely and quickly as we can.”
Wild said the delivery of the Elizabeth Line is now in its complex final stages and is being completed at a time of great uncertainty due to the risk and potential impacts of further Covid outbreaks.
He said: “We are working tirelessly to complete the remaining infrastructure works so that we can fully test the railway and successfully transition the project as an operational railway to Transport for London.”