Originally Posted by ManofKent
It's difficult to say because peoples feet vary so much and it depends on which Allen Edmonds last compared to which Trickers last.
+1 there's a lot of YMMV when it comes to shoe sizing and what fits one person vs another
I would safely call AE a "TTS shoe", and compared to Trickers seems to fit correspondingly (UK size being 1 full smaller than US size, so 10 USA is 9 UK). This is from "MY EXPERIENCE" which is from owning 6 pairs of Trickers and 3 Allen Edmonds. If you're in between half sizes (ie: AE 9 fits a bit snug but AE 9.5 is slightly loose), I'd go with that half size larger in Trickers (which would be UK8.5 / 9.5US in that example) because Trickers do not run long on their country lasts.
these are just general guidelines of course.