An investigation into the Garden Bridge Trust states that the Trust spent £50 million of public funds without producing demonstrable benefit and was a "failure for charity" which risks undermining public trust.
The Charity Commission's report on the trust concluded that while trustees fulfilled their legal duties in their decision-making, it criticizes the charity's approach to transparency and accountability.
The Garden Bridge project was a proposal for a pedestrian bridge across the Thames between London's Waterloo and Blackfriars bridges. The project collapsed in April 2017 after Dame Margaret Hodge's report for the Mayor of London found multiple failings at the scheme, with only £69 million in private donations raised towards its projected final cost of £200 million.
In its concluding report, the Commission advised policymakers to "think very carefully" before setting up an entirely new charity to deliver a singular public project or purpose. The regulator says it considers it "unlikely that the public would expect risks that are inherent in a major public infrastructure project to be outsourced to such a charity".
The Commission will update its approach when it receives applications from charities established for the sole purpose of delivering a publicly funded infrastructure project.
Commission Chair Baroness Stowell said "Londoners and taxpayers will legitimately feel angry and let down by the waste of millions of pounds of public money on a charitable project that was not delivered".
"I understand that anger and am clear that this represents a failure for charity that risks undermining public confidence in charities generally".
"While the charity was not mismanaged, the public would also expect, as I do, that the right lessons are learnt from this case, so that we don't see a similar failure arising in the future".
The Commission's report complements the Regulator's 2017 report into the management of trust, and sits alongside earlier reports by Hodge and the National Audit Office.