With planning permission due to expire this year, many outstanding issues remain, including spiralling construction costs and doubts around funding the maintenance of the bridge, said mayor Sadiq Khan. The private sector trust developing the scheme currently faces a funding gap of over £70 million; Khan said that it appears unlikely that it will succeed in raising the private funds required for the project. “I am simply not prepared to risk a situation where the taxpayer has to step in and contribute significant additional amounts to ensure the project is completed,” he said today.

The signing of operation and maintenance guarantees is a requirement of the Port of London Authority and is a condition of the planning approvals from the London Borough of Lambeth and Westminster City Council. Guarantees must be in place before construction can commence. It is open to the Garden Bridge Trust to seek to amend the PLA's requirement and the planning conditions from the local authorities.

In a letter to Lord Mervyn Davies, chair of the Garden Bridge Trust, Khan outlined his view that the continuation of the project will expose the London taxpayer to additional financial risk, both with regard to the bridge’s construction and its operation and maintenance.

Before making the decision, the mayor analysed the findings of Dame Margaret Hodge’s recent review into the Garden Bridge project (link opens in new tab).

In outlining the reasons for Khan’s decision not to provide any mayoral guarantees, today’s letter outlines a number of ways in which the project would expose the London taxpayer to additional financial risk. These include:

  • increasing capital costs of the project;
  • the risk of the bridge only being partially built; and
  • doubts over the establishment of an endowment fund to help meet future maintenance costs.