70's Maxi Couture Wrap "Bridget" Dress by Ossie Clark x Celia Birtwell

An Ossie Clark/ x Celia Birtwell 'Bridget' dress, early 1970's, labelled vintage UK size12, wrap-over style with padded waistband, crystal-pleated skirt

This dress is very rare and collector's item.
The wrap style should allow it to fit a variety of sizes. 

lightly inset shoulders: 13"
Bust: to approx 17" flat across from side seam to side seam
Waist: 11-13" flat across from side seam to side seam
Hips: open
Bodice: 14" from top of bodice to waist
Skirt: 40" from waist to hem

Modern Sizing Equivalent: XS-MED