A new report from the Corporation of London has warned that unless the funding problems on the Crossrail project are resolved, the £12 billion project will never be built.
The document - produced in response to the latest round of consultation - hits out at the complexity of current financial wranglings.
The move will disappoint many in the capital's architectural community, who reacted with delight earlier this year when the government finally announced that it would support a bill in parliament to enable the massive scheme to go ahead.
But the report stresses that this commitment could be hollow unless extra public cash is found. 'The government is understood to want to cap public funding for Crossrail at about £2-3 billion, whatever the total project cost, and has indicated that the City is expected to make a substantial contribution to the shortfall, ' it warns.
'Unless these complex funding issues are resolved in advance of the bill proceedings, there is every possibility that Crossrail will yet again fail to progress beyond the drawing board.
'Unfortunately it appears that Crossrail has concentrated its efforts to date on the railway engineering aspects of the proposals and has not paid sufficient attention to the need for an affordable scheme and a robust funding mechanism, ' the report concludes.