It's size 52 (42 UK) but wears small. I wear 42 in suits, but my other Rick leather jackets are both 54. I bought this in the MrPorter sale thinking the summer version might fit a little larger, but it only barely fits with a tshirt underneath. Full measurements are as follows:
Sleeve from armpit to hem: 21"
Body from armpit to hem: 17"
Back from collar to hem: 25.5"
The Mr. Porter tags are still attached, and I can return it up to next week for full refund. However, as the sale is now over, it won't be relisted on the site until January. So if anybody wants to grab a bargain, it will be listed here until Monday