I'd have thought the oldest surviving music in England is Morris Music where the words are accomanied by at least dance & some form of instrument???

The earliest references to Morris Dancing seem to be from about Tudor times and it seems likely that these were more of a form of court dances. William Kemp's famous dance to Norwich was not neccessarily what we would recognise as Morris today - after all he was one of Shakespeare's actors, and presumably his dancing would have been somewhat theatrical. Kemp would certainly not have been welcome in The Morris Ring as he danced with several female partners on the way ! Many of the tunes used in Morris dancing have their roots elsewhere, either as songs or dance tunes from other genres. Most of the Morris traditions extant today are probably no older than 250 years.

The British "Oral Tradition" was almost exclusively unaccompanied - if you were poor you couldn't afford to buy instruments. Instruments like pipes and simple drums could be homemade, but these would most probably been used for dancing to, rather than for accompanying singing.

Perhaps part of the problem is the term "Folk Music" - none of the old traditional singers would have used it to describe their songs. In fact I heard a story of one (greenhorn) collector who is supposed to have asked a traditional singer of considerable repertoire if he knew any Folk Songs. "Oh No", came the answer, "I can't play the guitar or anything like that".

I expect that in years to come, people will be asking "Un-synthesised Singing - How and Why".