Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_3 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7E18 Safari/528.16)

I should add that since the OP specified BA I would say not a chance that you can reliably carry it on. I had to be a bit persuasive to get an 18 or 19 inch roller on a BA flight a couple months ago.