System of a Down have sold out pretty much their entire large-theatre tour and the queues stretch round the block. Standing in them is an arse. What you're waiting for, though, is worth thinking about: Armenian-folk-influenced, melodically eccentric prog-metal complete with odd beards. If that’s not alternative I don’t know what is.

System are on top of their commercial game, displayed perfectly by them opening with ‘Prison’ - the crowd go mental, as suspected. The potential hits fly from their fingers as soon as they fly from the lips of the crowd: anthem in waiting, ‘ATWA’, unquestionably timeless classic, ‘Sugar’ and recent top 20 single, ‘Chop Suey’ all appearing before our ears. It is quite a marvel that a vast population here tonight are able to join Serj Tankian in every chorus, and indeed in every verse.

Showmanship was obligatory with this, oft random, heavy rock. The odd beards went some way to doing it but then a seemingly demented half-naked bald man called Shavo, with plaited jowl hair of course, gyrates his body – lurching and hurling in time to this music, ogling the crowd as if to encourage similar behaviour. He was playing bass, apparently. There was also a guitarist called Daron somewhere…didn’t see him, but I did see another half-naked guy with a straggly mess for a coiffure and a beard for each side of his chin, whose escapades around the stage can be likened rampant to a street urchin. John...the drummer...well he's the drummer. He sat quietly on his structurally immense drum-rig and hit animal skin unti it wanted to bleed again. Then there was this other guy…he ranted about drugs, about politics, about sex, about life, about removing tapeworm from butthole...

Serj Tankian - he stood out from the crowd of manic musicians helping to clutter the stage with sweat and grime. Tankian is possibly one of the most gifted and charismatically fervent ‘frontmen’ I have ever seen; possibly one of the most un-natural guitarists I have ever seen. He pulled out a guitar for ‘Aerials’. Put it away.

If you wanted to move, the crush of the weight of a hundred young men prevented this. If you wanted to stay still, something unseen made you move. You take what you’re given sometimes.