The health visitor was small in stature but her words had a big impact. Pointing at one primary head, she declared: “I can tell you on the day they are born which children you are going to be statementing - and you don’t do anything about it for another five years.” Then she swung around and pointed at the most experienced secondary head in the room, and said: “And I can tell you which are the children you are going to be excluding - 12 or 13 years later.”

It was a pivotal moment in the drawn-out consultations as Hertfordshire sought to merge education and social services into a unified department, the better to serve the interests of children at risk. Later, professionals from both sides agreed that there was evidence to suggest that the health visitor was right.

Ray Shostak, the director of education since 1997, is now head of the Children, Schools and Families service launched in April. The 20 per cent of social services staff dealing directly with children were combined with the education department. It is the first authority in the country to manage the task.

Mr Shostak will show you a presentation on his computer that dramatically illustrates why such changes were contemplated. One sequence starts with the fictional Carole: her family faces a crisis. Click the mouse and up come the eight branches of social services that might be called in. Another click produces six points of contact with education. Click again for voluntary services. A final click reveals nine links with health. The point is glaringly obvious: rationalisation would ensure services are more efficient.

What is surprising about such a radical step is that it was embraced with enthusiasm by a Conservative administration. Derrick Ashley, the deputy leader of the council and executive member for education during the changeover, says the idea had evolved with all-party agreement from the mid-1990s when the council had been under a Lib-Lab coalition. There was a tradition of strong links between education and social services and a consensus emerged that the two departments would do better if they were joined up.

What distinguished consultations from the start was their openness and the decision to build the new services from the child out. It all started with a blank sheet of paper.

As Mr Shostak put it to one of the many workshops held to thrash out details of the new department: “If you start with the children, what structure would you establish? And what are the barriers getting in the way of providing the best service?” The politicians and officers made it plain that the aim was not to make cuts: any savings would pay for the preventive work that was to be an important plank in the new strategy.

The idea is that there is one point of contact, one electronic file for each family rather than the 11 or so paper files kept by individual sections which made it almost impossible to get your elbows on the table whenever a case conference was called. Referrals are handled by a call centre in Stevenage which deals with all communications to the council, from getting a library book to enquiries about the environment. Once a call is logged, it is passed to one of four quadrant teams, a mix of social workers and education managers.

In the 12 weeks since the service started, there have been teething problems: some people say the all centre makes them feel remote, operators have needed special training and the software has not always lived up to expectations.

John Evans, the deputy director who led the steering group for the merger, talks of a robust dialogue between the two departments in the run-up to the changeover. They had very different philosophies: social services operate in a risk-averse, safety-conscious, hierarchy; education, which is concerned with development, is more accustomed to handling risk.

Senior staff in the new service had to absorb the knowledge and expertise of another discipline. Now they have to develop a common vocabulary and a new way of thinking. “You hear people saying ‘We’ve got to CSF this.’ ” he says.

Pauline Williams is an advisory teacher who works full-time with looked-after children. These are the children whose situation caused concern when it was revealed in 1998 that many authorities had no idea how they were faring or, in some cases, where they all were. She says Hertfordshire deserves credit because it was the first authority to give priority to such pupils.

However, the new service raises legal issues for her charges: “I am an advocate for my children. In the past, if they didn’t get into the school we felt was right for them, then we would take the local education authority to an appeals tribunal. Now we will be appealing against ourselves. Can we really take ourselves to an independent tribunal?” Not everyone is happy with the way the changes have been managed. While acknowledging that the general state of industrial relations is good, Dave Kellett, a senior shop steward for Unison, feels that education managers and social workers were given a disproportionate voice in the consultations; his members, mainly manual and admin workers, were asked too late for their observations to count.

“I find it ironic,” he says, “that the reorganisation was based on the doctrine of inclusion when this is how they treat the admin staff, the ones most likely to be in single-parent families, the lowest paid with the worst prospects.”

Steve Thornley, Unison’s branch secretary, believes the authority has not been bold enough in breaking down the cultural divide between the two departments. “It will happen in time,” he says, “but the management could have tackled the problem from the off.”

He believes a merger with health could have been achieved. In time, this may be a possibility. But Ray Shostak believes that, initially, it would have been “a bridge too far”.

“There is commitment there to enable us to join up, but there are a whole range of contentious issues - about confidentiality, about access to information.”

Gail Tolley, head of Stanborough school, Welwyn, and chairman of the Hertfordshire Association of Secondary Headteachers, says that many of her colleagues have experienced change anxiety. “There’s a tremendous goodwill for the new department,” she says. “We’ll put up with all the initial glitches because we’re all looking to the new service for preventive work to catch the problem children much younger.”

She told of a Year 9 girl in care who went on her first school trip last weekend - a history visit to the Normandy beaches and war graves. “This was a life-enhancing experience for her and it would not have been possible but for the staff released by the new service to go with her and offer support. This is why we are so positive.”

Additional reporting: Sue Jones