A planned bridge to span the river Thames with trees and shrubs has been scrapped after losing key support from the Mayor of London.

Sadiq Khan has written to the trust behind the project saying he cannot provide the maintenance guarantee needed for planning permission to be granted for the Garden Bridge, intended to run from Temple on the north side of the Thames to the South Bank.

The letter followed a meeting between the Garden Bridge Trust and City Hall.

A review of the project said £37.4m had been spent and it would cost taxpayers £46.4m even if it was cancelled.

Dame Margaret Hodge, who carried out the review into whether the bridge offered taxpayers value for money, said the project should be scrapped.

"I have been clear that this should not be allowed to happen. Accordingly, the GLA (Greater London Authority) is unable to provide Mayoral guarantees for this project.

"I regret that the significant expenditure of public funds and effort from both public bodies and the Garden Bridge Trust has not led to a situation where I can provide the guarantees requested."

Khan said the pledged funds the trust had detailed at the meeting on 20 April were lower than two years earlier "suggesting support for the project is not robust enough to generate the required funds."

The aim was to create an '' featuring an abundance of plants, trees and shrubs. Footpaths would have woven through the garden, creating a new pedestrian route

The previous Mayor, Boris Johnson, was a keen advocate of the bridge as well as actress and activist Joanna Lumley who had, according to the Guardian, conceived it as a memorial to Diana, Princess of Wales.