Sanctions & watchlists
UK OFSI consolidated list of financial sanctions targets
The UK's authoritative list of persons and entities subject to financial sanctions, published by the Office of Financial Sanctions Implementation.
The UK list matters directly in the islands, but each jurisdiction gives effect to sanctions through its own instruments. Check the local position too.
Published as downloadable data as well as a web page, so it can be screened against programmatically rather than eyeballed.
The Crown Dependencies are not part of the UK, and their sanctions regimes are implemented separately even where the substance mirrors the UK’s. Treat this as the starting point rather than the whole answer, and record which list you actually checked against.