Brexit did not change SWIFT membership for UK banks — SWIFT is global, not EU. But it did change which EU schemes UK banks could access, and reshaped the EUR-GBP corridor in subtle ways.
SEPA: the UK remained in SEPA after Brexit (third-country participant). UK banks can send and receive SCT and SCT Inst. The main practical difference is the EU "country code" for IBANs (GB stays as GB) and some bank-by-bank slowness to onboard SCT Inst.
TARGET2 / T2: UK lost direct access. UK banks now access T2 via correspondent banks in the eurozone (often Frankfurt or Paris). Adds latency vs pre-Brexit but for retail flows the difference is minimal.
CHAPS: unchanged — domestic GBP RTGS run by Bank of England. Migrated to ISO 20022 in 2024 on a new RTGS platform.
Sanctions divergence: UK now operates HMT OFSI sanctions independently from EU lists. Most large UK banks screen against EU + HMT to avoid double-cover gaps but technical differences exist.
Equivalence: UK CSDR / EMIR / MiFID equivalence is patchy and politically managed. For cross-border trade-finance flows, both UK and EU rules may apply.
For tracking: GPI is unaffected by Brexit. The UETR flow GB-EU is identical to pre-2020 with the same speed and trail visibility.
Minimally — most retail EUR-to-UK flows still complete within 1 business day. Corporate flows that needed direct TARGET2 access have added a correspondent hop.
No — SWIFT is global. UK banks continue full SWIFT membership.
Marginally — additional correspondent layer adds tiny friction but the FX market is competitive enough that retail rates are largely unaffected.
NI follows GB for payments infrastructure (CHAPS, FPS) but special protocol arrangements apply for trade with the Republic of Ireland.