This fabric is William Morris’ ‘The Strawberry Thief’. It’s 100% cotton.  This is a cropped / boxy cut.  The sleeves are 3/4 length and are designed to be loose fitting, so you can fit another layer underneath and wear it across the seasons.  
 
I try and buy vintage or deadstock wherever I can.  This particular piece of fabric came from someone who runs an interiors business; I tend to buy her last bits and pieces which works really well for us both.
 
Measurements:
63cm - pit to pit
59cm - Top of shoulder to bottom of shirt
50cm - sleeve length