Ofcom has indicated in its digital dividend review statement of December 2007 that it will allow cognitive access to the interleaved UHF spectrum as long as it can be satisfied that such access will not cause harmful interference to licensed users such as broadcasters and programme makers. It has now embarked on a body of work to assess the appropriate technical conditions that should be placed on cognitive devices such that these conditions can be met. This presentation describes the work that is underway and the initial results from that work, along with some indication of possible future directions.