This article is more than 3 years old

This article is more than 3 years old

The economic case for London’s proposed garden bridge is weaker than it was in 2014 when £60m of public money was committed to it, the Treasury has said.

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Signalling that government support for the controversial project may be in decline, a letter from the Treasury’s top civil servant said the overall case for supporting it even in 2014 was “finely balanced and subject to an unusually high level of uncertainty”.

Writing to Meg Hillier, the Labour MP who chairs the influential public accounts committee (PAC), Tom Scholar said the Garden Bridge Trust, which is behind the project, had yet to finalise planning consents, faced a continued funding shortfall and had already spent £22.5m of public money on pre-construction work.

“This suggests that the overall case for the project is weaker today than it was in 2014,” wrote the Treasury’s permanent secretary, also enclosing the original analysis of the business case requested by the PAC, which is looking into the proposed tree-and plant-filled pedestrian link across the Thames from Temple to the South Bank.

Scholar’s conclusions suggest government confidence in the much-delayed and over-budget project could be slipping, particularly in Philip Hammond’s Treasury.

Previous chancellor George Osborne had been a strong backer; in his 2013 autumn statement, he announced £30m in Treasury backing subject to a satisfactory business case being made.

This assessment was produced in May 2014 by Transport for London, which also committed £30m in public money for the Thomas Heatherwick-designed bridge.

The 2014 document concluded that there was an overall case for the structure, saying the public investment would be more than offset by benefits including improved pedestrian trips, increased tourism and “showcasing Britain”.

Since then a number of factors have changed, not least a rise in estimated construction costs from £150m to £185m and now an unknown sum which will be “substantially” more.

News of the increased costs came in the trust’s long-delayed accounts, released in January, in which the trustees warned that various uncertainties meant they were unable to conclude that the trust was a going concern.

Scholar’s letter to Hillier noted that the original business plan could have been strengthened in several respects, including a reliance on the potential business and property impact, which remained uncertain.

“Looking ahead, there are clearly issues still to be addressed, given the need to raise sufficient private funding and secure planning consents on the South Bank,” he wrote.

Although it was still possible that the bridge could provide net economic benefits, Scholar concluded, the case was very dependant on a series of assumptions, while there was “some risk of double counting” over certain benefits.

Originally only £8.2m of public money could be used before construction began, but this had since been increased to £22.5m, Scholar added.



London’s mayor, Sadiq Khan, whois sceptical about the project, unlike his enthusiastic predecessor Boris Johnson, and has warned that more than £40m of money would be lost to taxpayers if the bridge was cancelled.

A possible ebbing away of government support would be a further blow to the bridge, which has had a series of delays and is still awaiting the last element of planning approval for the south side.

The accounts showed that in the 17 months they covered, the trust raised just £13m in new private donations. It still needs to raise an extra £56m from donors, which would take six years at the current rate of fundraising.