Plans for a tram link across Waterloo Bridge received a blow on Thursday when Mayor of London Boris Johnson told a City Hall committee that he is "not intending to spend a lot more money on the Cross River Tram".
Mr Johnson was responding to questioning by London Assembly member Brian Coleman – a leading opponent of the Cross River Tram – at a meeting of the budget and performance committee.
"I am not intending to spend a lot more money on the Cross River Tram," said the Mayor.
Brian Coleman, who represents Barnet and Camden on the London Assembly, last week warned that the tram would increase traffic congestion in Camden and "greatly damage the character of Bloomsbury".
Last year former Mayor Ken Livingstone revealed that expenditure on the Cross River Tram to October 2007 was "in the order of £11.6 million". Total project costs are in the region of £455 million, with £6 million budgeted for development work during the current financial year.
The tram's backers in opposition parties have been swift to voice their disappointment at the Mayor's comments.
"Given how much work and money has already gone into this and given his transport strategy is still under review, it's staggering the Mayor would say this when he's not fully reviewed the case," says Lib Dem Caroline Pidgeon AM.
"The transport committee will next week be reviewing the case and how the tram can be funded and will put this to the Mayor as a matter of urgency."
The comments come just a few days before the London Assembly's transport committee holds a seminar to consider the case and prospects for the Cross River Tram.
"The new Mayor said he would listen to Londoners and that means listening to residents and businesses who are in favour of the tram, rather than just a Tory maverick who is against it," says Caroline Pidgeon.
"Over a thousand people have signed a petition supporting the tram. What the Mayor has failed to grasp is the tram is a solution which will not improve public transport in poorly served parts of south London but will also ease over-crowding on the Northern line, will help inward business investment in the city and will provide an environmental and fast north-south route.
"There is a huge cost to London of not going ahead with the Cross River Tram. I hope the Mayor will genuinely listen to the case for the tram and review his position urgently."
The pro-tram petition will be handed to Assembly members on Tuesday morning and formally tabled at a full meeting of the London Assembly on Wednesday.