Current sanctions on Serbia entail a prohibition to satisfy claims in relation to contracts and transactions the performance of which have been affected by measures imposed by UN Security Council Resolution 757 (1992) and related resolutions. The same sanctions regime applies in relation to Montenegro.
The UK has passed the Sanctions (Amendment) (EU Exit) Regulations 2019, SI 2019/26, which make amendments to a number of EU sanctions regimes to ensure (inter alia) that they continue to apply within the UK after Brexit. The Regulations will come into force on exit day....
Iraq 
Libya 
Haiti 
Serbia 
Montenegro 
Somalia 
Lebanon 
Afghanistan 
Central African Republic 
Sudan