Call to arms - how do you deal with an angry child?

I don't just mean one who has a strop because he didn't get his own way. I mean one who gets sooo angry when falsely accused of something. Elf was involved in a fight at after-school club yesterday; we were assured he didn't start it. Oh well that's ok then! 

 He'd been playing outside with another Year 1 and a Year R, with whom he collided and the little boy cried when he fell. The other Year 1 accused Elf of doing it on purpose. Elf got so mad that they ended up in fisticuffs. I have seen this anger when Elf is falsey accused, or when he is laughed at by adults, or indeed when interrupted. 

I myself get extremely angry when interrupted or am falsely accused, so can empathise. But I can temper my ... temper. He can't. The anger doesn't last long, a minute or two. (Unless he's been asked to sit out of playtime for refusing to apologise - when it turned out he was right not to!.) 

 I believe that this may have resulted from years of accusing Elf of doing things, when he was younger, because he usually was involved. But as he's grown up, he isn't like that so much anymore. He is now quite indignant when I think he might be at fault. Does anyone know how to deal with this? Elf is 6 in a few weeks. Do they learn to cope with the anger as they mature? Advise or experiences appreciated!