[zsas]

The Keep Calm and Carry On and derivative campaign is being done by tons of marketing campaigns. Kodak has one too:

http://exchange.kodak.com/projects/3...and_wallpapers

But, you do pose a good legal question, even if Ilford promoted a street campaign, do they sanction the selling of shirts with their logo? I doubt it...but they might look the other way too (my guess) because it is creating a buzz on the social net, for free....sometimes the any news is good news algorithm is in effect....

Personally, I wouldn't wear the shirt either...