The government has told London business leaders to find some more money for Crossrail to bridge a funding gap for the much vaunted £15 million project.
At a meeting on Thursday, Transport Secretary Ruth Kelly met the Campaign for Crossrail Group representing businesses supporting the scheme and called on them to come up with a cash contribution to bridge a funding gap believed to be "in the low hundreds of millions".
It is understood that Gordon Brown's Cabinet has now sanctioned the project.
Business leaders told Kelly that it may take weeks to come up with a solution to bridge the funding gap and Gordon Brown's aim of announcing the scheme at the Labour Party conference on 2 October is now in danger.
"The government has indicated that it has put together a funding package. It's nearly there. We are being told it is a small number of hundreds of millions rather than billions," said a source close to the Campaign for Crossrail. "On that basis she has put the ball back in our court and asked us to identify solutions to that funding gap, particularly from those businesses that stand to benefit most."
Interviewed in the Evening Standard, Transport Secretary Ruth Kelly called on businesses to "put real money on the table now".
"We need to see the colour of your money – then we'll be in a position to take a decision on affordability."