I wouldn't be so sure, it's definitely spread from London. The three biggest Cities/Towns in my area have all got mini 'riots' going on or being planned for the next few hours.. And I live in Oxfordshire, nothing happens here!
I'm genuinly surprised there's no significant trouble in certain areas of Newcastle area, that are known for having rival gangs (which are fairly close to where I live) causing trouble on the outskirts. Also extremely relieved. The most we've had was a small bit of trouble last night (few youths in a place called Elswick), and a reported break in at Gateshead. Thankfully nothing serious.