Derby days are great - my favourite is Lazio vs Roma but today is very tasty with Liverpool vs Everton and Arsenal vs Spurs. It will be a great day of football!!!! But which derby is England's biggest??? http://www.tibsnews.com/blogs/top-ten-english-football-rivalries/
What is the main London derby? Arsenal v Spurs or Arsenal v Chelsea, given that Chelsea havng the bragging rights to being the most successful club in London over the past decade and can probably more than match Arsenal's haul of trophies since the inception of the Premier League. I suppose one might be an intense rivalry , the other more "sporting?"
Ask yourself which derby's have spilled out onto the streets and resulting in riots? How many derby's make a man punch a horse? How many derby's have had a game where the crowd has tried to get the game abandoned because they were about to lose? The Mags may have loads of idiots but it does highlight how intense the Tyne/Wear, Wear/Tyne derbies are, and how much of an impact the game has on the people of the area, which is what derbies are about.
Liverpool Vs Man Utd probably more due to the profile of the two clubs. Arse Vs Spurs probably the next most famous. Liverpool Vs Everton Newcastle Vs Sunderland Man U Vs Man City are all pretty famous too. There may be others that are more intense or locally important- but those are the ones that everyone is familiar with and knows about.
There was a radio chat on the Celtic v Rangers match, and these 2 examples were classic. The Celtic fan who refused to get in a blue taxi. A Rangers fan who removed all the green smarties before he his kids have them as a treat.