What is changing with ID cards and passports in Oct 2021?
From the 1 October 2021, changes to government legislation will mean that most EU, EEA and Swiss nationals can only travel to the UK using a valid passport, unless they have applied to the EU Settlement Scheme by 30 June 2021 or otherwise have protected rights under the Citizens’ Rights Agreements.
From 1 October, an ID card will no longer be accepted for travel to the UK, unless the exceptions apply.
https://www.gov.uk/guidance/visiting-the-uk-as-an-eu-eea-or-swiss-citizen (Opens in a new tab)
Anyone travelling to the UK on an invalid travel document may be refused entry at the border.