<p>In the late 1970s, aggressive, young bands are forming across Britain. Independent labels are springing up to release their music. But this isn''t the story of punk. Forget punk. Punk was a flash in the pan compared to this. This is the story of the New Wave of British Heavy Metal, a musical movement that changed the world.<br><br> From this movement - given the unwieldy acronym NWOBHM - sprang streams that would flow through metal''s subsequent development. Without NWOBHM there is no thrash metal, no death metal, no black metal. Without the rise of Iron Maiden, NWOBHM''s standard bearers, leading the charge to South America and to South Asia, metal''s global spread is slower. Without the NWOBHM bands - who included Def Leppard, Motorhead, Judas Priest, Diamond Head and many others - the international uniform of heavy metal - the ''battle jacket'' of a denim jacket with sleeves ripped off, and covered with patches (usually sewn on by the wearer''s mum), worn over a leather biker jac