English Defence League demonstrations in Manchester last month 

What does it take for one 60-year-old man to run up to another 60-year-old man, whom he has never seen before in his life, and attack him in the middle of the street? The answer may never be entirely clear. As far as indicators of a complex situation go, a pensioner punch-up ranks pretty high.

It's Saturday 10 October, Manchester. An organisation called the English Defence League is holding the latest in a nationwide series of demonstrations against radical Islam. As with the previous demonstrations, it is being met with a counter-demonstration by Unite Against Fascism, a group recently established to fight the rise of the British National Party. UAF enjoys broad support from MPs (David Cameron is among the 50 or so who are signatories), but its infrastructure seems to come mainly from the far-Left. The Respect Party and the Socialist Worker have provided placards reading, "One Country, Many Cultures" and "Smash the BNP!" Red flags bearing the simple slogan "Revolution!" flap in the breeze. 

Although it is now the subject of intense media scrutiny, relatively little is known about the EDL. One thing that is known, though, is that it strenuously denies that it has anything to do with the BNP. The BNP leader Nick Griffin, in his infinite wisdom, has decided that the EDL is "a neo-con operation, a Zionist false-flag operation". But UAF thinks otherwise. It's convinced that the EDL is a BNP false-flag operation. So that's the short answer to the question of why the 60-year-old is behaving so badly.

He is a UAF "steward", equipped for this dubious duty with a yellow high-visibility jacket that also allows him to slip beyond the front line of the police-cordoned UAF protest. The main UAF ranks are chanting "Nazi scum — off our streets!" at a small EDL group 20 feet away, who are also being held back by police. But at first glance this man's jacket makes him look like a policeman or a member of the press, so he can walk right up to the EDL, jam a muscular finger in their faces, and reinforce the message: "You're scum and you're dumb, you're scum and you're dumb!"

The small EDL contingent is continuously harassed as the police manoeuvre it through the streets towards a secure holding zone in the middle of Piccadilly Gardens. UAF protestors are intercepting it and linking arms, trying physically to block the organisation that, they are adamant, "has no place on our streets". The tactic makes life difficult for the police, who are denounced from time to time as Nazi collaborators. The second sixty-year-old is with the EDL. He's a local, and is sporting a couple of small St George's cross and Union flag pins on his jumper. The high-visibility jacket approaches, screaming abuse, and the Mancunian asks, "Where are you from?" 

Is this a xenophobic gauntlet being thrown down? Or is the man just wondering from what distant place this zealot has been shipped, in order to play his part in the day's proceedings? Both men are white. "Get the f*** out of here, you piece of s**t," growls the man from the UAF, as he jostles him and plants a slap in his face. The Mancunian doesn't hit back, and the UAF man eventually disappears into the crowd.