But he admitted progress could be stalled because of the recession. And he insisted he was “confident” that building schemes over the next five years would go ahead as planned.

Mr Balls said: “Building Schools for the Future is a very ambitious programme.

“The Conservative Party want to divert £4.5 billion from that to other experiments. We think that’s the wrong thing to do and we’re working very hard to ensure Building Schools for the Future stays on track.

“Obviously, the pace at which we can move with that goal depends on the funds available to us, and that depends upon the state of the economy.

“We’ve got issues like unemployment and debt interest which are very substantial and affect how much money is available for schools and hospitals and police numbers and all those things.

“And so, rightly, we’ll wait to see the medium-term allocations the Chancellor can make.

“But we’re confident we can keep the Building Schools for the Future programme moving forward.”

Business Secretary Lord Mandelson warned that some college expansion proposals would have to be rejected, as there wasn’t enough funding to pay for them all.

A number of rebuilding schemes, including a planned expansion to Bournville College, had to be put on hold when it emerged the Learning and Skills Council had approved too many schemes.

Speaking as he visited Aston College in Birmingham, Lord Mandelson said: “These are a series of funding issues that we are looking at.

“We have had an unprecedented demand for expenditure in the further education sector. Many more bids for investment in colleges than we had planned for. It’s not easy because despite the expansion in investment and capital spending, there are so many more bids and requests that are difficult for us to meet in total. But we will do our best.”

Conservative MP Andrew Mitchell (Con Sutton Coldfield) said: “I very much fear that as a result of Labour’s economic failure, we are hearing the sound of brakes being applied and reverse gear being engaged.”

A Conservative Party spokesman claimed the Government was covering up the scale of planned cuts.

He said: “Figures from the budget show that capital expenditure is going to be reduced by 50 per cent over the next three years. Ed Balls needs to be honest about the budget and stop treating people like fools.”