Although detailed legislation for the energy labelling of post-brexit products is not planned until early October, the Department for Business, Energy and Industrial Strategy (BEIS) has stated in advance that for products placed on the UK market from 1 January 2021, UK flags will be required on their energy labels instead of EU flags (with the exception of Northern Ireland).
Corresponding compliant energy labels will be made available on the online tool "create an energy label" before December.