The re-use of 800 MHz spectrum for mobile broadband has led governments and regulators to instigate major programmes of interference mitigation. The resulting work programmes have led to a greater understanding of coexistence of TV and mobile services in the same band. This paper summarises the new and important advances in technical understanding of coexistence from the mitigation programme in the UK. The new licences for the 800 MHz spectrum in the UK required licensees to set up a company to mitigate interference. It is required to operate an interference prediction model, to communicate with the public, to provide practical assistance to mitigate interference and to report on its performance to an independent Oversight Board. In practice, television interference has been reported by only a small number of those households predicted to be at risk. A combination of operational experience, practical observations and research have led to improved modelling, more targeted communications and a revised approach to viewer support.