Entering the UK ‐ ETA - SoCraTesUK/socrates-uk GitHub Wiki
This is a page to share experiences applying for the Electronic Travel Authorisation, which now (April 2025) applies to EU citizens, as well as other non-UK nationals, to be able to visit the UK.
Direct link to apply online (they push their app quite a lot, but it is also possible to apply via the governement website if you prefer)
The ETA costs £10 and lasts for 2 years or until your passport expires. Some people have reported getting the response to their application within 5 mins.