"The backbone of surprise is fusing speed with secrecy." So said military philosopher Carl von Clausewitz. It is a message that the government seems to have taken to heart when it comes to children's trusts.

While everyone was imagining that any decision to roll out the children's trust model would wait until the 35 pathfinders had been evaluated, the government had other plans. It pushed ahead with them, setting out its vision in the green paper Every Child Matters for all local authorities to establish children's trusts by 2006, a year before the evaluation findings are released.

This decision to pay lip service to evidence-based policy will give other local authorities no chance to learn from the pathfinders' successes and mistakes.

Eileen Munro, reader in social policy at the London School of Economics, says: "It's a very strange way to behave. It suggests an ambivalent attitude to rigorous research which may come up with findings that they can't control."

And there are discrepancies between the pathfinders and the long-term vision. Some pathfinders are a commissioning model, others are providing services, and some are doing both. Some models focus on a small section of the population - for example, services for disabled children only - others work with those aged up to 19 or up to 24. Some serve entire local authority areas, others just parts. But, by 2006, all local authorities must have a children's trust to commission services for all children, young people and families in its area.

If it seemed an intelligent move for some pathfinders to choose to work with just one service, it would probably be the best way to go for the other local authorities coming on board, says Munro. "With a lot of tasks in life you start on a small scale while you work out how to do it. You can see the sense in getting it right with disabled children's services first so you have a blueprint to work from."

Also of concern is the omission of adults' services from the green paper as many problems experienced by children stem from their parents. Domestic violence, drug abuse and mental illness are the three biggest background factors in child protection referrals. Yet trusts will not be in a position to tackle these, says Munro.

At the same time as being pathfinders, 13 of the 35 are piloting the Serving Children Well model devised by the Local Government Association, the Association of Directors of Social Services and the NHS Confederation. This coalition wants the government to roll out their model rather than children's trusts as they feel agencies are being pushed down a path that is too narrow.

LGA programme manager Helen Goody says children's trusts should encompass more than health, social services and education. "Children come into contact with most services, whether they are leisure, housing or environmental health. Serving Children Well is about all services."

And there is concern that the government is coming at trusts from the wrong end. "You don't put structures in place, then decide what you are going to deliver," says Goody. "Structures are further down the line. You decide what you are trying to deliver for children and you decide how you will deliver them and what structures will have to be in place to achieve this."

Although the LGA can understand why the government wants to push on with its agenda, Goody warns that cultural change is necessary. "Structures will not make people work together better. The government thinks by putting structures in place the cultural changes that need to happen will follow, but most people say that's not true."

Indeed, an oft-expressed view from practitioners and academics is the need to return to relationship-based services rather than be driven by procedural and bureaucratic processes and structures.

"One of the best ways to promote good working together is by having stable working relationships, so by changing it yet again you disrupt the relationships and the networks," says Munro.

Add to that the recruitment problem and, if it is not careful, the government will simply be reorganising empty offices.

The success of children's trusts will rely on multi-agency working, but the underlying problem of trying to co-ordinate services is something that has been a primary goal in children's services for at least 30 years. The fact that it is not sorted by now suggests it is a big problem.

"The government underestimates the different conceptual framework of professions and undervalues how important these differences are," says Munro. "There's a problem of interdisciplinary working together. The idea that they should merge into some composite profession is misguided."

The challenge of multi-agency working should not be underestimated, agrees Sue Berelowitz, head of families and schools support at West Sussex Council, one of the 35 pathfinders. She says: "We have made tremendous headway but we know there's a long road yet to be travelled. The critical issue is whether we are all prepared to face the challenges together and I think we are. But cultural change takes time."

West Sussex is also trailblazing the identification, referral and tracking system. As a trailblazer the council has to disseminate information across the south east. Berelowitz can see no reason why pathfinders cannot share their evolving learning with other local authorities. She says that even where pathfinders are dealing with a specific service valuable lessons will emerge that others can benefit from.

"We are using our pathfinder status to help us explore and develop procedures and protocol for multi-agency working and delivering services on the front line. We are discovering what works, what needs to be changed and what needs to be improved."

Whether non-pathfinders will have the luxury to do this, or whether they will be thrown in at the deep end with little experience and no evaluation findings from which to learn, remains unknown.

Berelowitz believes that the thrust of the green paper - of working in partnership to deliver more integrated services - is something that should be taken on board now. "We had decided to go down this route because we believed it was right before becoming a pathfinder. You don't have to wait for a definitive direction from government before going down this route if it's right for your area."

But, given all the complexities, many do not believe the timetable of 2006 is achievable. "If we are serious about outcomes then this isn't something we can do in a year or two," says Goody.

It seems the government would be better off with less haste, otherwise it may come as no surprise if children's trusts fail to deliver with the desired speed.