Interesting explanation re: blue pents, Manton. And a good reminder to re-watch Brideshead Revisited; it's been at least 10 years.
I agree that grey is clearly the superior choice for most rigs, but I still think a dark blue flannel would look better than grey in at least some instances - a grey herringbone tweed, for example. Boom. Pop on an open-collared OCBD and you're done.
Black shoes for Pb.