In addition to the provision of advanced concepts and controller tools to support the safe management of the anticipated growth in traffic, the SESAR programme also looks at the overall organisation of controller teams. In the framework of Release 2, eight NATS controllers were involved in a 12-day operational validation exercise testing the concept of a multi-sector planner operating environment in the London Area Control Centre (LACC). Stephen Pember, SESAR project manager at NATS, explains the concept and preliminary results of the exercise.