Plans for a tram system in west London have been rejected by one of the three councils affected by the route.
The trams were due to start running in 2013
The £650m scheme, which would run from Shepherd's Bush to Uxbridge, was unanimously opposed by the London Borough of Ealing.
Labour members who had previously supported the scheme did a u-turn and called for the West London Tram scheme to be scrapped.
The final decision on its future now lies with Transport for London.
The project has been deeply unpopular with local people who claim it will increase congestion and affect trade.
Last year, a public consultation on the tram scheme showed 59% of people opposed it.
Transport for London (TfL) was due to apply in December for permission to start work on the West London Tram, but has put it back until the summer.
Ealing Council leader Jason Stacey said they will now have to put together a case against the trams in case it goes to a public inquiry.
"There's a lot of people who live just off the Uxbridge Road," he said.
"The trams would create congestion all the way down the Uxbridge Road and push traffic down side streets.
"People are very, very worried at what the impact would be on them."
TfL had said previously it hoped to start work on the system in 2009 and to have the first trams running in 2013.