Thomas Edison of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp. On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William E. Sawyer and was, therefore, invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's,
Government incentives for plug-in electric vehicles Peugeot ePartner, Renault Kangoo Z.E., and Smith Electric Edison. The number of eligible registered plug-in electric vehicles passed the 25,000 unit milestone in January 2015. , the number of eligible registered plug-in electric cars that have benefited with the subsidy totaled 94,541 units since the launch of the programme in 2011. , the number of claims made through the Plug-in Van Grant scheme totaled 2,938 units since the launch of the programme in 2012. About 90,000 plug-in electric vehicles have been registered in the UK up until December 2016, including over 85,000 plug-in hybrids and all-electric cars, and about 4,000