The charity behind the failed attempt to build a "garden bridge" over the River Thames in central London spent almost £53.5m on the scheme, new figures show.
A report published by Transport for London yesterday says that just under £43m of this was public money, made up of £34m from TfL and £19m from the Department for Transport.
The Garden Bridge Trust, which was set up to build and run the proposed bridge, announced in August 2017 that it would be ending the project and winding up after Sadiq Khan, the Mayor of London, withdrew his support because of concerns that the charity would not be able to raise the £185m it needed to complete the scheme.
TfL said it was publishing documents relating to the scheme as part of its "continued commitment to transparency".
Boris Johnson, the previous Mayor of London, had made up to £60m of public funding available to the charity, split equally between TfL and the Department for Transport, the report says.
But not all of these funds were paid, with about £37m paid so far and a further £5.5m available to be claimed by the scheme as part of the cancellation of the project and the winding up of the charity.
TfL said the £5.5m final payment was about "40 per cent lower than it could have been". It said the publication of the report formally ended its involvement with the project.