Niki Lauda had signed an initial letter of intent to leave his 1984 championship-winning McLaren team and join Renault for 1985.
During the year he was approached by the Williams team, who used turbocharged Honda engines, about driving for them in 1985 as a replacement for Jacques Laffite who was moving back to Ligier.
Lotus finished fourth in the Constructors' Championship, scoring 71 points and three wins, two for Ayrton Senna and one for Elio de Angelis.
Renault had decided that funding a Formula One team was not worth attempts developing technology for their road cars and the bad PR generated by their continuous failures to be competitive had been the final straw.
Ironically for Warwick, he would later regret his decision to stay in Renault as the 1985 Williams FW10 and its Honda engines won four races in 1985, including giving Mansell his first two career wins, the second of which was the South African Grand Prix that saw the French F1 teams, including the State owned Equipe Renault, boycott the race under the direction of the French Government in protest to South Africa's Apartheid policy.