We have had some inquiries regarding whether EU identity cards can still be used instead of passports and, unfortunately, the answer is: NO. Not since October 2021.
Here is what the UK Government website states:
Irish citizens can continue to enter and live in the UK.
EU, EEA and Swiss citizens can travel to the UK for holidays or short trips without needing a visa. In other cases, find out if you need to apply for a visa to enter the UK.
You can cross the UK border using a valid passport which should be valid for the whole time you are in the UK.
EU, EEA and Swiss citizens can continue to use the automatic ePassport gates to pass through the border on arrival.
You cannot use an EU, EEA or Swiss national ID card to enter the UK unless you:
In these cases, you can continue to use your national ID card to enter the UK until at least 31 December 2025.