The latest breakdown of funds raised for the Garden Bridge project shows that the total amount pledged for the scheme has dropped by £14 million since May.
Soon after taking office in May this year, Mayor of London Sadiq Khan released a Garden Bridge Trust document showing that £143 million had been raised – including £60 million from the public purse.
At that time the bridge was expected to cost £175 million to build.
Last month Garden Bridge Trust chair Lord Davies told the BBC's Newsnight programme that "one or two" donors had dropped out – and that the scheme's cost had risen to £185 million.
This week TfL laid bare the full extent of the widening funding gap by publishing an updated schedule of donors.
The latest fundraising total shows that the trust has raised £129 million – which leaves the project £56 million short of the (rising) capital cost of the bridge.
TfL has also published a new breakdown of the public money [PDF] that has so far been spent on the Garden Bridge.
Transport for London and the Department for Transport are each contributing £30 million to the project, with TfL also responsible for passing the central Government money to the Garden Bridge Trust.
So far £26.7 million of public funds has been paid to the Garden Bridge Trust.
Before it signed its funding agreement with the Garden Bridge Trust in July 2015, TfL had already spent nearly £10 million on the scheme. This amount will be counted as part of TfL's £30 million contribution.
Of that TfL money, £8.4 million was paid to engineering firm Arup. Designers Heatherwick Studio received just £52,425 at that stage.
Two key officials involved in the early stages of the Garden Bridge project at City Hall and TfL – deputy mayor Isabel Dedring and TfL's Richard De Cani – have since gone on to take jobs with Arup.
By July 2015, TfL had spent £750,000 on legal fees and £150,000 on public consultation.
• Meanwhile the Garden Bridge Trust had been expected to conclude its South Bank lease negotiations with Lambeth Council and Coin Street Community Builders this summer. A final decision has now been delayed till November.