I haven't been able to access this thread for a long time, so it's developed a lot since I was writing on it a while ago.
    A few points: whatever the Shambles may say, or in whatever way we would wish the world to be, I think our race/cultural backgrounds are very important to how we perceive folk music, as central a component of the Art of Identity as anything. There are often contoversies on Mudcat, for example, as to whether certain songs(say "The Wild Rover") are Irish or English...or nether, or both. But it is perfectly obvious that people's country of origin is quite likely to affectr how they approach a question like this, we all have group loyalties,or disloyalties, like it or not.
And as I often pontificate on black music, or white music, or any other topic, I ought to come out myself. I am a bogstandard white middle-class male. My main areas of interest are NW English traditional music, but my specialist area is southern USA folk music, particularly Louisiana, cajun an, creaole and zydeco. I have played many many gigs with JC Gallow, the black musician from Maou, Louisiana, who frequently gusts with the Boat Band, when he tours with us in England. I have also worked with Gino Delafose's band, when I was the only white guy in a black zydeco band. I also do a lot of musical work with refugees in Stoke-on-Trent (England), so I have close experience of how folk music is used by recently arrived immigrant groups to maintain their cultural links, and I have also observed at close hand how immigrant musicians can integrate(or not integrate) into the general cultural life of the country. I also have the standard white liberal musicians' exaggerated(?) respect for black musical forms. I was brought up on jazz and blues, worshipped Leadbelly from the age of 12, etc etc. Which is why I like reminding Poppagator that Amadee Ardoin was black, and emphasising the importance of black musicians to cajun, ot whatever. Like most British musicians, also, I have an inordinate love for calypso, ska, reggae and so on.(though like a lot of post 50-year olds, I dont go a bundle on gangsta rap).
    Now, you may think this is an egotistical ramble through my own mind, but I do believe we need a little of our own histories to know where we are coming from, and let others know the possible background of our prejudices.
    And to the matter in hand: English musicians, like African musicians, are and have always been ingenious and quick to learn. Any African musical person arriving in England in 1700 would have figured out what to do with a fiddle in ten mintues, whether or not they came from north or sug-Saharan Africa. Likewise any English fiddler(or a substantial percentage of English fiddlersa), when coming across a black dancer doing the solo hornpipe spot in an English pub in 1720, or finding a group of black fiddlers giving it some in Liverpool in 1750...well, they are going to react just the same as me faced with Leadbelly in 1957, or the Stones with Muddy Waters, or anybody with Louis Armstrong or Jimi Hendrix. They would say "Give me a slice of that".
    We really do not need a thriving plantation culture(as in America), or a millions strong sub-culture(as we have now), to explain black influence on indigenous English music in the 18th or 19th century. These things happen easily and quickly. And they will have happened in London, or Liverpool, or Bristol, or Whitehaven, to start with. Not in Little-Piddling-in-the-Mire!. London and Liverpool was where the blacks were, and where there was work in plenty for fiddlers and dancers. That's how, and where, cultural transfers happen.
   The sea-change in English fiddle music from 1700 to 1800(and American music) was very much black influenced. That is what I am suggesting. And no, I cant prove it, Neither can anyone else. I would put it in the category of the Bleeding Obvious. I just hope some universities will direct a bit of research money in that direction, to reinforce some of the background information.