Rachel Reeves could seek billions of pounds in private funding to build a highway and tunnel across the River Thames east of London, according to reports.
The chancellor wants to try to complete the project with private sponsors to avoid any costs to the state budget, the insider said. Financial Times.
They spoke to two Treasury sources who added that investors in Lower Thames Crossing would benefit from the toll road if they backed the project.
During the election campaign, the Prime Minister Keir Starmer and the Labour Party have said they want to spark a building boom in Britain to revive the country's infrastructure.
However, since taking office, Ms Reeves has cut a number of infrastructure projects, citing a £20bn “black hole” in the public coffers.
Ms Reeves will reportedly try to limit the returns investors can receive after investing.
The project is expected to cost up to £9 billion, a figure that has already risen from £5.3 billion to £6.8 billion.
Alistair Watson, a partner at law firm Taylor Wessing, said: “Given these costs, the project could require significant public funding to significantly 'de-risk' the project for private investors.”
The project has so far cost around £800 million and involved 359,000 pages of planning applications.
Lower Thames Crossing has previously warned that major UK projects are being delayed by construction restrictions.
Chief executive Matt Palmer told the webinar: “Back in 2008 we passed a Planning Act that worked very well until about 2016. Since then, all these delays have become more and more problematic, meaning that getting projects delivered in the UK is probably the most challenging it has ever been.”
Tony Travers, a professor at the London School of Economics, says the private sector will find the project attractive given its proximity to London.
He said: “This is a new project so people won't be able to complain that they are paying for something they used to have for free.”
Express.co.uk has approached the Labour Party for comment.