The UK government introduced its own Conformity Assessed (UKCA) Marking programme for items to be sold in the GB (England, Scotland, and Wales) market on January 1, 2021. Northern Ireland has its own set of rules, which are outlined here. There is no mutual recognition of marks between the UK and EU
What does the UKCA mark indicate?
The producer declares that a product fulfils the UK Regulations as stated in the applicable Statutory Instruments by affixing a UKCA mark to it and placing it on the UK market (SIs).