Reviewed by deekay from Canada on Tuesday, March 3, 2009
Sizing is definitely "British" -I normally wear size 44 sport coats, 16-1/2x 35/large shirts but upsize sweaters due to "athletic build" (OK-plus middle age spread). Like other reviewers I went up in size. Johnstons size 48 fit comfortably- 46 would have been trim/too tight for my taste.
So, one size up as a minimum in my experience, depending on your preferred fit.
Beautiful, soft sweater- very pleased with purchase.