Labelled size 16 USA. Usually you add 4 to get the UK size equivalent, but I'm not convinced this is fitting a UK 20. Perhaps better suited to a UK 18: pit to pit measures 20 inches, shoulder to hem 27 inches. Note, this is quite a longline jacket. Best to measure a current garment of your own in a similar style to make sure this blazer is the right fit for you.

Not in great condition: several small holes/nicks/pulls, and some marks/stains to the inner lining. Please see photos.