The nature and scale of the task to decommission the UKs legacy nuclear facilities has been historically poorly characterised and highly uncertain. A key objective is a comprehensive understanding of the work to be done and the associated costs. An understanding of the nature of legacy waste is an essential part of the decommissioning process. The ability to locate, characterise and correctly partition the waste is key to this strategy and will contribute to a significant reduction in the costs associated with the decommissioning effort. The fusion of three-dimensional (3D) spectroscopic gamma-ray and stereoscopic optical images offers the potential for a step change in the performance of imaging systems. The ability to locate, identify and measure the dose of gamma-ray emitting material is of crucial importance. Existing technology falls short of the desired performance characteristics. This presentation will discuss the evaluated performance of a number of gamma-ray imaging systems and offer prospects for the deployment of such systems in the near future.