Wimbledon's expansion plans suffered another blow after Wandsworth Council voted against its proposals.
The All England Club (AELTC) wants to build 39 tennis courts, including an 8,000-seater show court, on the former site of Wimbledon Park Golf Club.
Officers at Wandsworth Council recommended councillors refuse planning permission earlier this month.
The Mayor of London's office will have two weeks following Wandsworth's decision to deliver a verdict.
Mayor Sadiq Khan could also opt to take over the application himself - a course of action also within the power of Michael Gove, the secretary of state for leveling up, housing and communities.
Merton Council, which is responsible for all but the most northerly part of the land, voted in favour of the scheme last month.
Its officers accepted the proposals would result in "physical harm" to Metropolitan Open Land, but concluded "very special circumstances" meant "substantial public benefits would outweigh [the] harm".
However, Wandsworth Council's planning committee voted to refuse the expansion plans at a meeting on Tuesday.
"Naturally, we are disappointed by the London Borough of Wandsworth's decision," AELTC chief executive Sally Bolton said.
"Our proposals will deliver one of the greatest sporting transformations for London since 2012, alongside substantial benefits for the local community.
"We firmly believe the AELTC Wimbledon Park Project offers significant social, economic and environmental improvements, including turning 23 acres of previously private land into a new public park, alongside hundreds of jobs and tens of millions of pounds in economic benefits for our neighbours in Wandsworth, Merton and across London."
Iain Simpson, the chair of Save Wimbledon Park, said the outcome was "very heartening", adding: "The councillors unanimously recognised the crucial point that this application does not justify so much harm to Metropolitan Open Land, our precious Green Belt."
The expansion would allow Wimbledon qualifying to take place on-site - in line with the other three Grand Slams. Qualifying for the grass-court Grand Slam is currently held three-and-a-half miles away in Roehampton.
The All England Club has also promised to create a new 23-acre public park in the spirit of the original design of landscape architect Capability Brown. At least seven of the grass courts would be made available to the local community for the summer weeks which follow Wimbledon.
There has been strong local opposition to the plan, with members of the Save Wimbledon Park organisation protesting outside the chambers where Wandsworth Council made their decision.
They highlight the issues of the environmental impact and the loss of trees and open spaces.
An attempt could be made to challenge the lawfulness of the way the decision was made - on the grounds of illegality, procedural unfairness or irrationality.
But the bar remains high, as only a very small number of these cases succeed each year.
A 30-year-old legal covenant may also form part of a challenge. When the freehold of the golf course was transferred from Merton Council to the AELTC in 1993, the club agreed "not to use the [land] other than for leisure or recreational purposes or as an open space".
This will have to be resolved before any work can begin on a development.