ES News email The latest headlines in your inbox twice a day Monday - Friday plus breaking news updates Enter your email address Continue Please enter an email address Email address is invalid Fill out this field Email address is invalid You already have an account. Please log in Register with your social account or click here to log in I would like to receive lunchtime headlines Monday - Friday plus breaking news alerts, by email Update newsletter preferences

The future of the Garden Bridge project suffered a blow today after Sadiq Khan said he would scrap the proposed Thames crossing if elected to City Hall.

The Labour mayoral candidate said the horticultural oasis, designed by Thomas Heatherwick, did not represent value for money as it required £60 million from the public purse.

His decision came as Labour-run Lambeth Council effectively pulled the rug out from under the project by putting negotiations over the land required for the Bridge on hold.

Lambeth leader Lib Peck said in a letter to the Mayor that she would reconsider the town hall's position if different options for funding the project from private sources were put forward.

She added: "It is also becoming clear that future mayoral support for this scheme is weakening."

Boris Johnson slammed the decision as "a shameful exercise in political posturing" while City Hall insiders described the move as a "shocking U-turn".

Mr Johnson said: "The Garden Bridge will be an iconic addition to London's skyline and a driver of jobs and growth in the area.

"Given that for more than two years Lambeth has been heavily involved and hugely supportive of the project, this would appear to be nothing more than a shameful exercise in political posturing.

"Lambeth has already granted planning consent for the bridge. I have no doubt it will be built."

The decision, however, is a blow for the project's supporters, led by actress Joanna Lumley, as well as almost eight in ten Londoners who said they backed the plans in an Evening Standard poll several weeks ago.

Mr Khan had previously said he would review the £175 million plans for the Garden Bridge between Temple and the South Bank.

But today he said he would spend Transport for London's £30 million contribution on transforming Oxford Street into a pedestrianised tree-lined boulevard instead.

The Standard understands that some of this money has already been spent.

The public funding was intended to encourage private sector investment in the project - already standing at just under £100 million - and in recognition of the transport benefits it would bring, as well as new jobs and investment for the South Bank. It will also go on installing lifts.

Mr Khan's likely rival in the mayoral race, Tory Zac Goldsmith, has been supportive of the Bridge, suggesting the battle for its survival could continue for months.

Mr Khan told the Standard: "In principle I love the idea of the Garden Bridge, but what we were sold is a long way from the reality we now face. It has become another of Boris Johnson’s white elephant projects – like the Cable Car which is used by few at the cost of millions of pounds.

"I believe it no longer represents value for money. This was supposed to be an entirely privately funded project costing £60 million, but the overall cost has tripled, and £60 million is being paid for out of the public purse, with a possible maintenance cost of £3.5 million a year – for a bridge which will often be closed to the public for private events and won’t be open overnight."

The Tooting MP said he would put the money towards pedestrianising Oxford Street although such a huge project would take millions more in funding and many years to complete.

There would be no guarantees that the Treasury would transfer the £30m it has already committed to the Garden Bridge.

Ms Peck said: "I have consistently said, during a time of severe spending cuts putting £30million worth of public funding towards this new bridge isn't justified.

"So while it might have other merits, it is surely wrong for TfL to issue a blank cheque, particularly given the financial pressures they face from the Chancellor.

"Disappointingly, since I first raised these issues in June, there seems to have been little progress in attracting alternative funding from the private sector, so we are now suspending further lease negotiations until the Mayor gives us the reassurances I have written to him asking for."

Bee Emmott of the Garden Bridge Trust, said: “We are surprised at the letter particularly given how closely we have worked with Lib Peck and Lambeth Council for the last two years.

"We have been very clear from the outset that the public funding is a way to stimulate private contributions, which will make up the greater amount of the funding.

"As Lambeth knows, a significant amount of funding has already been spent during this preconstruction phase following Lambeth granting planning permission."