No matter how terrible and awful an event, someone somewhere will usually benefit. Until Wednesday's attack in Woolwich, the English Defence League was going the way of many street based far-right groups: riven with multiple factions and in-fighting. Social movement theorists (if you’re ever lucky enough to meet one) will tell you that keeping a movement together is harder than founding one. People were slowly drifting away, perhaps losing faith that the EDL was achieving anything. Then, in just 24 hours, the EDL’s Facebook page tripled in size – from 25,000 to over 75,000 – with new vim and vigour, re-fuelled on anger.
The EDL’s identity is closely wrapped up with the army. The group emerged in 2009 out of the United Peoples of Luton, which Stephen Lennon (aka Tommy Robinson) helped form when an Islamist group protested the Royal Anglican Regiment's return from duty in Afghanistan. A survey I ran of EDL supporters in 2010  found that the only institution they trust – by a considerable margin – was the army. As a rallying call for the EDL, brutally murdering a soldier in broad daylight is just about the most effective action imaginable.
The effect on the EDL of this murder will be profound. One of the great dangers now is a cumulative spiral of reprisal and counter-reprisal between EDL groups and their enemies, both online and off. The EDL and the Islamist groups it opposes have always fed off each other, attending each other's demonstrations and whipping themselves up to a state of mutual hatred. When I interviewed Robinson back in 2010 , he told me that they they were "sick of being caged in like animals" by the police, and were on the verge of holding unannounced demos instead. This is the nightmare scenario: the EDL hitting multiple locations simultaneously, resulting in weekly street battles with counter-demonstrators before the police can get there. We would see a spiralling, self-reinforcing anger on all sides. Academics call this 'cumulative radicalisation'.
Judging by last night’s events – documented by  the NS's Daniel Trilling – and the vitriol, death threats, and general hardening of language online since the murder (both by and at the EDL) this is now a real possibility. When I spoke to Robinson in 2010, his overriding feelings were urgency and frustration. He told me that "something has got to give. If nothing happens, something drastic might happen. I don’t know what it might be". I’ve never seen the EDL as angry as it is now - their supporters' frustration will surely diminish as time passes, but, for now, it has been given a new lease of life.