The charity behind the capital’s Garden Bridge project has revealed substantial risks to whether the project can go ahead.

In a report released today, the Garden Bridge Trust says that the project is no longer a “going concern” – meaning its finances are subject to collapse.

It adds that costs could far surpass the estimated £185 million needed to complete the project.

Its accounts for 2016 filed with Companies House show a shortfall of £56 million, and further disclose that it has yet to secure the land on the South Bank of the Thames for the Bridge’s southern base.

The documents add that the trust may need additional funding that would not be repayable should the project not proceed in the first half of this year.

The accounts conclude that “in a worst-case scenario” the trust might have to consider “whether the project remains viable”.

London Mayor Sadiq Khan estimated that £40 million of tax payer’s money would be lost if the project was terminated. The Trust has further raised £69 million through private investment.

Lord Mervyn Davies, Garden Bridge Trust Chairman, said: “The last external estimate of the total project cost of the Garden Bridge was £185 million but, due to the hurdles still to be cleared and the ensuing delays, the final cost could substantially exceed the formal estimate.

“Due to material uncertainties in existence ahead of finalising these accounts trustees are unable to conclude that the trust is a going concern and feel it only appropriate to flag these risks.

“It is hoped that these will be resolved over the months ahead but since a number of these risks are outside of the control of the trustees, they recognised that if this is not possible they will need to consider the further delay to the project, and in a worst-case scenario, whether the project remains viable.”