The attached spreadsheet has a list of countries that we currently issue UK EUR1's for. If you cannot see the country you want to issue the UK EUR1 for please check that it has not been added to the list at https://www.gov.uk/guidance/uk-trade-agreements-with-non-eu-countries
Even if deals are marked provisional application UK EUR1's can be issued.
If it is not on either list you cannot issue a UK EUR1. If the agreement states that origin is claimed by self-certification such as the EU - UK or the Turkey UK agreement then the exporter uses an invoice declaration. Again for these agreements we cannot issue an UK EUR1. You should also advise exporters they need to ensure that there goods qualify for preference according to the rules of origin for their goods for that agreement.
HMRC have create a page where an updated list of ways to claim preference for all trade agreements which can be found here: https://www.trade-tariff.service.gov.uk/rules_of_origin/proofs?country=AT&day=4&month=10&year=2023
Last updated December 2023