We get those here too, and they all seem to have something in common - its cultural, not religious. They tend to occur in close knit 'redneck' communities who migrated to the UK from backcountry regions with very backwards, patriarchal, often tribalistic cultures, and generally haven't made much effort as a community to integrate into/engage with British society, preferring to isolate themselves and cling to practices from their regions of origin. I don't think they have grown in number - but far more are being reported, and logged as honour killings, than previously was the case. Fortunately its actually being taken seriously now, along with the issue of integration vs multiculturalism - so one good thing has come out of the riots and the backlash from 9/11 at least.