Originally Posted by
Aviatrix
I would still recommend using the EU document to enter the country. It simply makes no sense to use a non-EU document if you can use an EU one. As an EU citizen you enter the UK as a matter of right, they can't turn you away, they're not even supposed to ask you any questions such as "how long are you staying?"
Absolutely. Even though EU citizens have right of entry into the UK, and technically not having a passport to prove this shouldn't stop them, tempting fate is not a good idea. It's not worth the hassle or the risk to present a non-EU document.