Csmatyas
Note that what was said earlier is a simplification and not what Apple actually says. You should perhaps read what the warranty says. For the UK it is also a little bit more confusing.
First, the warranty does not say Apple will definitively refuse service outside the country of purchase. What it says is Apple "may" restrict service. In practice Apple sells regionally designed devices. What Apple will frequently do is completely exchange a faulty device for a refurbished model. This means you immediately get a working device. However, since one region won't necessarily have any models from another region, they "may restrict" service. So to play it safe you should never assume, for example, you can get a European iPhone repaired in the USA.
Second, Apple Products and Consumer Laws in the United Kingdom
says:
"Apple may restrict service for Apple Watch, iPad and iPhone to the EEA and Switzerland."
This is confusing because the UK is not even a member of the EEA (which is not the same as the EU). Still, that's what Apple's UK warranty document says, and implies that the UK warranty does extend to EEA countries. That includes EU countries.