1. A method of selecting a route for a network circuit in a telecommunications network, comprising: storing, in a database, first model data representing a first model of the telecommunications network, the first model data defining network nodes and connections between network nodes in the telecommunications network; receiving second model data representing a second model of the telecommunications network, the second model data defining node groups, each representing a plurality of network nodes of the first network model, and interconnections between node groups, each representing connectivity between node groups in the first network model; searching the second model data to select a route from a start node group to an end node group, the route specifying a plurality of node groups connected by interconnections in the second network model; searching the first model data to select a circuit route from a node of the start node group to a node of the end node group, the circuit route comprising a plurality of nodes connected by connections in the first network model, the nodes of the circuit route being selected from the nodes of the node groups specified by the route.