The Brooks Brothers Extra Slim FIt is typically wider (at the chest) than the Charles Tyrwhitt Extra Slim Fit. However, the cuts of the shirts differ for the different neck sizes, so at some neck sizes the BB is slimmer and at other neck sizes the CT is slimmer.
The numbers I have are as follows. For the 14.5 inch neck the CT Extra Slim is 40.2 inches at the chest (garment measurement). The BB Extra Slim is 39.5 inches at the chest (garment measurement).
Thanks for the info. The link in your signature is very helpful as well. Do you recall when those measurements were taken? The current CT size chart states: "The above chart shows the measurements of the actual product." when giving the 36 inch chest size. Perhaps they have updated the fit since your measurements were taken?
EDIT: nvm, I missed the asterik exception where the chest measurement refers to the "body measurement."
I find it amazing how I can find blazers with 34 to 36 inch chest measurement yet there are no dress shirts that size. Why are dress shirts bigger than the blazers which are worn on the outside?