Oh, well, with Van Morrison you're talking about something completely different from what I thought the topic was. Van Morrison---a Rock/Hard Rock/Metal/Progressive singer? I think of him as a Soul or R & B singer, one of a handful of Brits (okay, and Scots/Irish/Welsh) who sounds like he comes by it naturally, not in a forced, self-consciously "gotta-try-to-sound-soulful" kind of way. For a real good example of Van's whiteboy soul, listen to the incredible trading of lines with Richard Manual in The Band's bitchin' song on their Cahoots album, 4% Pantomime. Really, really great. Richard Manual, another white brother who can be mentioned in the same sentence as Ray Charles, Big Joe Turner, Muddy Waters, and (almost) Howlin' Wolf (NOBODY comes close to Wolf in my book). Richard (R.I.P.) was one of Eric Clapton's favorite singers, and probably his favorite white one. Another UK singer with the same gravitas is Little Stevie Winwood ;-).