Today the Court of Appeal will decide whether the government can take action against a judge's verdict before Christmas that the cuts were 'unlawful'. In this article for RTCC Robb argues that policy certainty is the most important factor for solar providers in the UK, without the threat of retrospective action. She also draws attention to the real threat facing the industry: the proposal to relate the Feed in Tariff to the thermal efficiency of the building on which the system is installed, as measured by its Energy Performance Certificate (EPC). Having blown the FIT budget with the massive rush of installs prior to 12 th December, what we need now is some certainty and sustained support without stops and starts. For this reason it is tempting to wish that the government wins the appeal against Friends of the Earth, Solar Century and Homesun. If the government loses the appeal there will be another 43.3p gold rush which will consume the 'reallocated' budget up in a matter of weeks. This is no good for jobs or for industry sustainability. On the face of it, if the government wins, the 21p rate would stand and we could all get on with our jobs. Or could we? If the government wins its appeal this means they will have been given the right 'retrospectively' to change the tariffs applying to installations made between December 12 th and the end of the consultation period. In the original High Court hearing the judge made the