Sure Start, the flagship government programme designed to lift children out of poverty and set them on the road to educational achievement, has failed to show any measurable impact, The TES can reveal.
An official evaluation, due to be published in July, is expected to find little or no evidence that the ambitious project's early targets have been met.
The revelation will come as an embarrassment to Labour, which has promoted Sure Start as one of its major success stories and which has pledged a massive expansion during its third term.
Around pound;1 billion has so far been spent on Sure Start, and up to Pounds 1.8bn per year has been pledged to help build a nationwide network of 3,500 new children's centres under the programme.
Margaret Hodge, the children's minister, said: "It is early days and we have always said this was a long-term programme, but it is true some of the early targets were probably not very sensible.
"But if you look at Sure Start together with early education and the new concept of children's centres, I think we are powerfully on the route to witnessing a stunning transformation of the life chances of this generation of children."
But according to a former senior civil servant who was one of its main architects, Sure Start cannot so far be proved to have worked.
Norman Glass, a former deputy director in the Treasury who is now chief executive of the National Centre for Social Research, said that while anecdotal evidence suggested parents and staff were enthusiastic about the scheme, the evidence did not support them.