Social workers in Haringey are working with police officers and NHS child protection workers on all initial screening of cases.
The move is one of many by councils to change the way social work teams are structured in the light of increasing referrals to children's services.
The child protection specialists from each sector will be based in the same building and will look at all cases together when they come in.
Director of Children's Services at the Council, Peter Lewis, called the move "ground-breaking" and added that "uniquely" the council had also managed to get each team's IT system installed in the same room.
"We now have a comprehensive suite of systems which provide vital information to help us safeguard vulnerable children," he said.
"Good communication between partner agencies is so important and we have been working hard to improve this. We already work closely together, and this seemed the natural step forward.
"By creating a joint team, physical and structural barriers are broken and all agencies can truly work together to protect our most vulnerable children," Lewis said.
The new multi-agency team began work last month and will link closely with emergency duty protection teams. The teams may also carry out joint visits, where they deem it necessary.
Lewis said that, while the move required investment to get started, the team had already noticed "dramatic improvements" in the timeliness and efficacy of assessments. An evaluation of the new approach is currently underway.
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