For the 1986 F1 season Guy Ligier received decisive help from the French Ministry of Sport to maintain the supply of Renault engines. The units used by the team were prepared by Mécachrome, while those that the Lotus received were officially built and tuned by the Renault works unit. The JS27 was essentially a development of the 1985 JS25 designed by Michel Tetu. The Ligier was classified in fifth place among the constructors, thanks to the discreet placings of René Arnoux and Jacques Laffite; the latter had to be replaced by Philippe Alliot after an accident at the British GP.