Transport for London has been forced to suspend the award of the £1bn Silvertown tunnel contract following a legal challenge by the rival bidder.
In May, TfL named the Riverlinx consortium as the preferred bidder to build the new tunnel, which will link the Greenwich Peninsula and the Royal Dock in east London and had been due to open in 2025.
Details around the deal were still being discussed and the confirmation of the contract was due this summer with work due to start this year.
The consortium comprises Aberdeen Standard Investments, BAM PPP PGGM, Cintra, Macquarie Capital and SK Engineering & Construction (SK E&C).
However reserve bidder STC – which includes Hochief and Dragadios – has lodged a legal challenge.
A TfL spokesperson said: 'We are disappointed that our reserve bidder, STC, has decided to challenge the outcome of our procurement process for the design, build, finance and maintain contract for the Silvertown Tunnel. We are awaiting further details about the claim and will respond to them in due course.'
STC is reported to have lodged its claim with the construction court last week.
The commencement of the court proceedings by the reserve bidder, STC, automatically results in a legal suspension of TfL’s right to award the contract to Riverlinx.
TfL said that it will be looking to award the contract and begin construction on the project as soon as possible.
Victoria Rance, co-coordinator of the Stop Silvertown Tunnel Coalition, said: 'We are very glad that this scheme has been delayed. It will give time for the mayor to sit down with his advisers top re-think the project.
'TfL's own figures, suggest Silvertown will increase traffic, increase CO2 emissions, and make overall air pollution worse across adjacent boroughs.
'This eye wateringly expensive scheme is clearly incompatible with the mayor's climate and air quality goals, and he should take the opportunity to abandon it now.'