According to EU regulations, UK citizens are supposed to get the same market place benefits as citizens in other EU countries. A discrepancy in iTunes pricing is just the thing to get investigated and sorted out. And quite right.
"Consumers' Association has submitted a letter of complaint to the OFT urging them to investigate what appears to be anti-competitive and discriminatory behaviour by iTunes against UK consumers." - Consumers' Association
Apple's current defence is that the economic models in each EU country has an impact on pricing of iTunes downloads. Sure, but EU regulations say that that doesn't matter. And apart from that, Apple had pretty much nothing else to say.