Question: The 1984 British Grand Prix was won by what driver who is the only one to have been a champion for both Ferrari and McLaren? 
Sentence (from "1984 British Grand Prix"): The 1984 British Grand Prix (formally the XXXVII John Player British Grand Prix) was a Formula One motor race held on 22 July 1984 at Brands Hatch, Kent, England.
Relevant evidence: Yes