Why do I know about the band "One Direction"? Because I have a teenage daughter. It's the same reason I am acquainted with the work of Justin Bieber. I was surprised to learn that that the members of One Direction were English, but not surprised that they were put together by Simon Cowell in the classic boy-band tradition.
However, I was actually shocked to discover that Mr. Cowell's incredibly successful organization apparently overlooked the fact that there was already an American band with the same name, with a federal trademark registration. There is nothing to prohibit the band from using the "One Direction" mark in England but they appear to be infringing on the US band's federal trademark. The US group has of course filed suit. This trans-Atlantic state of confusion has gone on for decades. For example, the English Beat had to adopt the "English” qualifier in response to a claim by the LA group, “The Beat.” Likewise the British band Squeeze was briefly known in this country as "UK Squeeze". Conversely the British band "The Birds" allegedly took legal action against the American "Byrds" when they made their famous first trip to the UK back in the '60s.
What amazes me is that anyone could be unaware of a trademark registration in this day and age when the US Patent and Trademark Office has an up-to-date online database of pending and registered marks and any band can be readily Googled. It used to be much more complex. In order to search up the availability of a record company name or band name, you had to undertake a costly and not always accurate media search. You also had to contend (as you do now) with the fact that a party can generate common law rights in a mark even without a registration. However to overlook a pending registration or an actual registration is just strange.
As for One Direction US v. One Direction UK – I predict a settlement before too long.