I see Jim Waterson at Buzzfeed is crediting this blog for the “then” picture of David Cameron:
That appeared here (I think for the second time) in November last. Note, as I did then, that the boy Dave was wearing, not just his sarong, but also his trues Blues Brothers tee.
As I recall, the originals source (remind me, someone) suggests the image comes from a trip to Thailand (or could it be Burma?), snapped by a “former girl-friend”. Now, there a story to be told.