Plans to build a tram network in Merseyside face possible collapse after the government said on Monday it would not put more money into the scheme.
Merseytram faces the axe unless more cash is found
Transport Secretary Alistair Darling said Line One of the Merseytram project had risen in cost from £225m to £325m in just over three years.
He told MPs in a written statement that he was still committed to the project, but not "at any cost".
The project's organisers confirmed they were to meet the government.
Merseytravel, the authority behind Merseytram, said they were heading to London in a bid to save the project.
Last week Liverpool City Council approved the plans but said it did not want the cost burden falling on the taxpayer.
It said it was "deeply disappointed" with Mr Darling's announcement.
Mr Darling said he had taken the decision because Merseytravel, the body running the project, had said the government's expected contribution would rise from £170m to £238m.
"I appreciate that Merseytravel has made every effort to keep costs under control," he said.
"However, it is clear that costs remain significantly higher than those that I approved, and that this scheme is an expensive way of delivering these transport benefits for Merseyside.
"In the light of all the information I have therefore concluded that I cannot approve the proposal for Line One."
'Ready to go'
Liverpool City Council, which was helping fund the scheme, said it was an "important part of the regeneration of Liverpool".
"The city council had given the scheme its full backing and, aside from a few issues which still had to be ironed out, the whole scheme was ready to go," a spokesperson added.
"We had been working extremely hard with Merseytravel in order to deliver this project in time for the city's year as European Capital of Culture 2008."
The first of the routes, from Liverpool to Kirkby, was due to open in 2007.
'Wake up call'
The private sector consortium, Downtown Liverpool In Business (DLIB), said the message to industry was clear: "Liverpool lacks the collective drive to turn dreams into reality."
"The failure to secure such a modest transport scheme so close to the city's Capital of Culture celebrations highlighted the city's lack of leadership."
DLIB Chairman, Frank McKenna, said: "The message this decision sends to those outside the city is that Liverpool cannot deliver on prestigious, strategic projects.
"The delays caused by the fact there were so many agencies involved, all failing to find agreement, has cost the city dear.
"This is yet another example of local politicians and officials in Liverpool arguing among themselves rather than getting the job done.
Mr McKenna added: "This should be a final wake-up call to Liverpool's powerbrokers to put their squabbles to one side and work together for the good of the city."