The Garden Bridge currently has a funding shortfall of at least £55.9m.
In the wake of a BBC Newsnight programme, which suggested the bridge needs a further £52m, the Garden Bridge Trust has announced it is in fact £55.9m off its target.
This is because the projected cost of the Garden Bridge is now £185m, rather than the previously quoted £175m.
However, if the BBC's claim that the funding gap was previously £52m, then the new £10m spike would bring the funding gap closer to £62m.
Why the sudden spike in cost? The Garden Bridge Trust says it's due to "hold-ups in land negotiations and planning matters".
There have been a number of disputes over the bridge, including the suggestion that Thomas Heatherwick's commission to design to structure was not entirely transparent.
The Garden Bridge Trust has also asked for the government’s £15m underwriting of the project to be extended by a year, to September 2017. This money is taken from the allocated £60m of existing taxpayers' money, and does not, says the Trust, involve the spending of any more public funds.
Does the continued rise in cost projections mean the bridge may become altogether nonviable?
A spokesperson for the Garden Bridge Trust told Londonist: "We have raised an unprecedented amount for a project of this type and construction hasn't even started.
"We are confident that we can raise all the funds needed for the capital cost and the ongoing costs. We have a number of advanced discussions with potential donors."
The question is how many of those potential donors will sign on, and whether, in the meantime, the cost of the bridge will rise even further.