Hate to go there, but it depends what you mean by 'traditional'; i.e. can it just mean that traditionally a song is sung by a number of different people within certain communities? If so, then 'The Cadgwith Anthem', 'Three Score and Ten', 'Song of the Moor (Devon & Somerset Staghounds)', 'Cornish Lads' and a number of other songs are undoubtedly traditional, even if the original author is known, and such songs may well have been subject to the 'folk process' before they were totally accepted within those communities - see the 'Three Score and Ten' thread.

By the way, re Keith Marsden's 'Bring Us a Barrel', some years ago, the chorus of this appeared on an outside wall of a quite prominent pub in West London, with 'Old English Pub Song' as the accreditation! Sadly, it's no longer there.

Barbara