The opening of London's troubled Crossrail project has been delayed once again and is now set to open in Autumn 2021, according to Transport Commissioner Mike Brown.

Transport for London has today confirmed that the central London section won't open until Autumn 2021 at the earliest due to signalling issues, putting the £18bn project three years behind schedule.

Crossrail, also known as the Elizabeth Line, was due to be opened by the Queen in 2018, running via Reading and Heathrow Airport in the west to Shenfield and Abbey Wood via Woolwich in the east.

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Most of the stations are now nearly complete, but the project has been hit with a raft of delays and seen its original £15.4bn budget rise to £17.6bn.

As reported by ITV, TfL commissioner Mike Brown today told the London Assembly that more time was needed to test the trains and signalling systems before the project could open.

When questioned by budget committee leader Gareth Bacon, Mr Brown confirmed that TfL had revised its expected opening date to between September and December next year.

He said that "if there is of course, at this moment unforeseen, safety critical risk that emerges with the signalling system, then clearly that could put some further time and cost delay on the project."

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Mr Brown said today that the new Crossrail bosses who joined in December 2018 underestimated how far the project was from being completed, and that the project was in "great disarray."

“The sense was that the major challenges ahead was the commissioning of the railway system – the signalling and the rolling stock,” he said.

“What wasn’t envisaged was the scale of unfinished and uncompleted work on the stations and the station systems."

Mr Brown told the assembly members that he expects there to be a progress update from Crossrail bosses on Thursday.