Steve Sinnott of the National Union of Teachers pleaded with the Government to extend the deadlines - and quoted Children Now's exclusive survey to drive home his point that many councils were not ready for such a massive change.
He said the Government needed to take note of the survey's finding that one third of councils were not working towards the 2006 deadline for establishing children's trusts (Children Now, 1-7 September). He also warned of the dangers of a recruitment crisis if, as the survey suggested, few people wanted to apply for the director of children's services position.
"Teachers, I believe, are committed to the principles of Every Child Matters and the principle that we have to ensure children's needs are met in a co-ordinated way," he told an NUT fringe meeting at the Liberal Democrat conference in Bournemouth.
"We want the Bill to be implemented and we want it to work. But there are some examples of local authorities going speedily down the route of bringing together children's social services and education. You'd have thought these would be enthusiastic about doing things quickly. But Surrey, which has gone down this route, is now saying give these reforms time; don't rush these things, get the principles right and give it time to work through."
According to Sinnott the Children Bill should not be about structures.
"It should be about culture. These things need to be done at the correct speed: one in which there is proper capacity for professionals to work together."
Annette Brooke, the Liberal Democrat children's spokeswoman, said: "Everyone is being urged to do something now but we haven't had reports back from the trailblazing pilots looking at databases or pooling funds.
"We'd be in a better position to work on this if we had the information about how it will work. We are being asked to vote on a Bill in a vacuum."
Sinnott said children's services would only be improved if teachers and social workers were less undervalued by society and more highly paid.
"I will fight like billy-o for teachers and in doing so I will fight like billy-o for children," he said.
Elsewhere at the conference, food spokeswoman Lady Miller said the party would establish "food for life" targets to ensure schoolchildren receive proper nutrition, including 50 per cent of ingredients coming from locally sourced produce.
She blamed poor school diets on the Conservatives who, she said, had closed school kitchens and sacked cooks, leading to poor concentration and hyperactivity.
"At a single stroke they turned a generation away from eating a midday meal prepared with prime ingredients into a generation who ate snack food on the run," she said. "Vending machines filled the hunger gaps that inevitably appeared and children's moods swung on sugar highs and hunger lows."
- See Analysis, p12.