Alan,
The BBC in conjunction with EFDSS initiated a collecting project some time in the early 1950s - have the details here somewhere.
Peter Kennedy was appointed head of the project and fellow collectors included Sean O'Boyle, Seamus Ennis and Bob Copper.
During the period of its activity several thousand items were recorded, songs, stories tunes, folklore - you name it.
The recordings were catalogued and put onto acetate discs - a set was housed at the BBC and another at Cecil Sharp House; the Northern Ireland BBC also had a copy.
Some of the recordings formed the basis for a series of programmes, 'As I Roved Out' presented by Kennedy, and appeared in a few others such as MacColl's 'The Song Carriers'.
The BBC then appeared to lose interest in the collection, and without their permission or that of any of the performers, Peter Kennedy, who had somehow acquired a copy, began to issue them commercially on his company 'Folktrax'. Because of who he was, nobody did anything about this, and he continued to sell them (mainly unmastered poor quality cassettes) right up to his death a few years ago. Kennedy's set of the recordings are now the (legal - I understand) property of Camsco (Dick Greenhaus).
I do not know the state of play with the BBC recordings, though I think they still exist, partially anyway. They occasionally put in an appearance, usually to be taken the piss out of by people who know nothing about folk music (The Rambling Sid Rumpo Syndrome).
A full set, now digitised, still exists at Cecil Sharp House, accompanied by a magnificent annotated catalogue.
Over the last few years the Dublin based Irish Traditional Music Archive, and (I think)The Folklore Department at UCD have acquired sets of the Irish material - I don't know if the School of Scottish Studies have the Scots material, but they should have.
The collection comprises the finest set of field recordings of British song and music ever made - excuse my surprise in your not knowing about it and the circumstances surrounding it.
Jim Carroll