It's definatley more underground. A lot of the gigs I go to it's normal for there to be no more than a 100 people there (and thats on a good day) I've seen UK metal bands play to crowds of 50 or so people in the back rooms of pubs and stuff.
In some parts of the country these bands do pull bigger crowds. In places like Brighton and (parts of) London in particular they tend to have bigger followings. We have Ghostfest here in Leeds every year which always features the cream of the UK metal crop, still, its held in a pretty small club and theres only ever a crowd of around 200 (at the most) in attendance.
We used to have a really solid, thriving metal scene in Leeds but it seems to have died out as of late, all our best bands have split now
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