All Saints Athene 100% Silk Long Dress Maxi size UK8 possibly 10 or even possibly 12. See measurements below

Pit to pit 17.5 inches

Length at back to approx 53 inches

Racer back

Side seam pockets

Floaty grey silk

Side slits starting 12 inches above hem

Used condition, repaired at back seam, mark on front 7 inches below neckline, although  this is hidden in volume of fabric  when I wear it. See last two photos. Reflected in price.

Classic All Saints style. Beautiful vintage dress.