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? 

Context articles: 2001 British Grand Prix
1982 British Grand Prix
Tooned
2010 Canadian Grand Prix
John Taylor (racing driver)
Niki Lauda
1984 British Grand Prix
2000 British Grand Prix
1985 British Grand Prix
1989 British Grand Prix

The 2001 British Grand Prix (formally the LIV Foster's British Grand Prix) was a Formula One motor race held on 15 July 2001 at Silverstone in Northamptonshire, England.
 It was the eleventh race of the 2001 Formula One season.
 The 60-lap race was won by Finnish driver Mika Häkkinen for the McLaren – Mercedes team, who managed to overtake the driver in pole position, Michael Schumacher.
 Schumacher, driving for Ferrari, finished in second behind Häkkinen, whilst team-mate Rubens Barrichello gained the final spot on the podium.
 It was Häkkinen's first victory of the season.
The 1982 British Grand Prix (formally the XXXV Marlboro British Grand Prix) was a Formula One motor race held at Brands Hatch on 18 July 1982.
 It was the tenth race of the 1982 Formula One season.
 The 76-lap race was won by McLaren driver Niki Lauda after he started from fifth position.
 Didier Pironi finished second for the Ferrari team with his teammate Patrick Tambay third.
Tooned is an animated cartoon by McLaren starring Jenson Button, Fernando Alonso and comedian Alexander Armstrong; and formerly, Lewis Hamilton, Kevin Magnussen and Sergio Pérez.
 It was aired on Sky Sports F1 before the start of each Formula One race.
 The first season, which starred former McLaren driver Lewis Hamilton aired from the 2012 British Grand Prix onwards.
 The second season aired from the 2013 British Grand Prix onwards.
 All episodes can be watched on McLaren's YouTube channel and the Sky Sports F1 website any time after the premiere.
 The episodes are a little more than 3 minutes long.
 On 16 May 2014 it was announced on McLaren's YouTube channel that a season 3 was in progress.
 It was announced when Jenson Button was shown a picture of his 2014 team mate Kevin Magnussen's character on "Tooned" and also added that 'the production of Season 3 was going well'.
 It was announced by McLaren on 19 October 2016 that "Tooned" would be making a return, featuring Fernando Alonso and Stoffel Vandoorne (and possibly Button).
The 2010 Canadian Grand Prix (formally the XLVI Grand Prix du Canada) was the eighth round of the 2010 Formula One season.
 It was held in Montreal, Quebec, Canada at the Circuit Gilles Villeneuve on 13 June 2010.
 This was the first Grand Prix to be held on the North American continent since the 2008 Canadian Grand Prix.
 The race was won by McLaren driver Lewis Hamilton, his second Canadian Grand Prix victory, ahead of teammate Jenson Button and Ferrari driver Fernando Alonso.
 This race was Scuderia Ferrari's 800th start in a World Championship event as a team.
John Malcolm Taylor (23 March 1933 – 8 September 1966) was a racing driver from England.
 He participated in five World Championship Formula One Grands Prix, and also participated in several non-championship Formula One races.
 His Formula One debut was on 11 July 1964, at the British Grand Prix at Brands Hatch driving a one-litre, 4-cylinder, Cooper–Ford T73, where he finished fourteenth, 24 laps down, after an extended pit–stop due to a gearbox problem.
 Taylor did not compete in the Formula One World Championship in 1965, but continued to drive in non–championship races.
 He returned to Grand Prix racing in 1966 driving a two-litre Brabham–BRM for privateer David Bridges.
 His first race that season was the French Grand Prix at Reims where he scored his one championship point.
 There followed eighth places at both the British Grand Prix at Brands Hatch and the Dutch Grand Prix at Zandvoort.
Andreas Nikolaus "Niki" Lauda (born 22 February 1949) is an Austrian former Formula One driver and a three-time F1 World Drivers' Champion, winning in 1975, 1977 and 1984.
 He is currently the only driver to have been champion for both Ferrari and McLaren, the sport's two most successful constructors.
 More recently an aviation entrepreneur, he has founded and run two airlines (Lauda Air and Niki).
 He is also Bombardier Business Aircraft brand ambassador.
 He was also a consultant for Scuderia Ferrari and team manager of the Jaguar Formula One racing team for two years.
 He is currently working as a pundit for German TV during Grand Prix weekends and acts as non-executive chairman of the Mercedes AMG Petronas F1 Team.
 Lauda owns 10% of the team.
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.
 It was the tenth round of the 1984 Formula One season.
 The 71-lap race was won by Niki Lauda in a McLaren-TAG, with local driver Derek Warwick second in a Renault and Ayrton Senna third in a Toleman-Hart.
The 2000 British Grand Prix (formally the LIII Foster's British Grand Prix) was a Formula One motor race held on 23 April 2000 at Silverstone Circuit, England, United Kingdom.
 It was the fourth race of the 2000 Formula One season and the 53rd British Grand Prix.
 The 60-lap race was won by McLaren driver David Coulthard after starting from fourth position.
 His teammate Mika Häkkinen finished second with Michael Schumacher third for the Ferrari team.
The 1985 British Grand Prix (formally the XXXVIII Marlboro British Grand Prix) was a Formula One motor race held at Silverstone on 21 July 1985.
 It was the eighth round of the 1985 FIA Formula One World Championship.
 The 65-lap race was won by McLaren driver Alain Prost after he started from third position.
 Michele Alboreto finished second for the Ferrari team and Ligier driver Jacques Laffite came in third.
The 1989 British Grand Prix (formally the XLII Shell British Grand Prix) was a Formula One motor race held at Silverstone on 16 July 1989.
 It was the eighth race of the 1989 Formula One season.
 The 64-lap race was won by McLaren driver Alain Prost after he started from second position.
 Nigel Mansell finished second for the Ferrari team and Benetton driver Alessandro Nannini came in third.