From the 31 January 2025, Safety &Security GB ENS will be required on imports into GB from the EU.
Organise your Stena Line North Sea route S&S GB ENS here
Organise all other route S&S GB ENS with CustomsLink

From 1 October 2021 EU, EEA and Swiss citizens can only travel to the UK using a valid passport

Anyone travelling to the UK on an invalid travel document is liable to be refused entry at the border.