It'll be a form of The Cruel Mother, I should think. Walter Scott based his It was an English Ladye Bright, in The Lay of the Last Minstrel, on it, and quoted this verse:

She lean'd her back against a thorn,
The sun shines fair on Carlisle wa':
And there she has her young babe born
And the lyon shall be lord of a'

The only recording I know of with that refrain is by Linda Adams, and appears on the Fellside CD Ballads (FECD 110, 1997). She learned it from one of her schoolteachers, an Ann Dickens. Where Ms. Dickens got it we do not know (no sign of it in Child or Bronson) but apparently a form of it appeared in Sidney Gilpin's Songs and Ballads of Cumberland (1866). I don't know where else you'd find it.