Ok, name as many new bands from the UK that were playing metal between 1985 and 1990. (discluding bands formed before '85)
Easy enough eh?
Now name the ones that didn't come from a punk background.
The only ones I can think of are Sabbat and Blood Money (also Atomkraft, but they'd formed in '79), and maybe Wolfspack, the rest were either initially punks (Carcass, Bolt Thrower, Onslught, Amebix etc etc etc), or a bad attempt to rip off Metallica (Xentrix etc). Or shitty 'fun' thrash (Acid Reign, Lawnmower Deth etc)
But were there any more bands from the period who weren't from a punk background, who played in the ol NWOBHM tradition? I don't think there were many...
The same could be asked of French bands, but the other way round (most seemed to be just Heavy metal 'sped up' ala Loudblast, ADX, Killers etc. There weren't really any bands that played full on Thrash or Death metal bar Aggressor or Mutilated...).