Date based on a note in Britten's diary from 3 Jan 1931 which mentioned vocal parts being copied out for a musical evening that day for 'Song', and the parts for this piece are on the same manuscript sources.
Soprano part with signature.
1 page of 4 page manuscript [4r-4v]
Pencil; 23.7 x 31 cm. Paper manufacturer = The B.F.Wood Music Co. Shares a volume with other sources. See Related Records.
Archive
https://www.bpacatalogue.org/archive/BBM-i_saw_three_witches-1-7