Arsenal - Chelsea

While they never considered each other primary rivals, as two of the top clubs in London there has always been strong needle between the fans dating back to the 1930s. The Arsenal and Chelsea rivalry has been more recently considered an important derby, after Chelsea's rise to the top class of the Premier League in 2000s, when the two started to compete constantly for the English championship. According to an internet survey of fans in December 2003, the Arsenal fans who responded to the survey said that they considered Chelsea as their third rival, after Manchester United and Tottenham Hotspur. Those Chelsea fans who responded to the survey said that they considered Arsenal as their main rival, however Tottenham and Fulham are their more traditional rivals.
http://bacherlorpadsinlondon.blogspot.com/