Fulham is a wealthy business district in London, and Tottenham fans are relatively richer; "Hammer" West Ham United is a typical working-class club, but Upton Park in east London has been the residence of Bangladeshi refugees since 1970s. Traditional West Ham fans have moved out of the city, and naturally they are getting closer and closer to Cambridge in the northeast. Chelsea is also a traditional labor club. After Stamford Bridge became a high-end business district in London, prices soared, and traditional Chelsea fans naturally went downhill, so they had to continue to move south, so they approached Millwall, where football hooliganism was the most serious problem. Because London is an international metropolis, more fans lack the traditional regional view, so it is easy to support Manchester United and Arsenal, the two best teams in recent years, as their home teams.
So I don't think there are more fans at Tottenham Hotspur than Arsenal and Chelsea anywhere (including London) at present. Twenty years ago, Tottenham was always an art football, as a yardstick to judge the team's level (Bergkamp supported Tottenham since childhood), but Arsenal before Wenger could hardly attract neutral fans.