UK VAT Number

Detects United Kingdom (and Northern Ireland XI) Value Added Tax registration numbers. Standard trader numbers are GB followed by 9 digits; branch traders use GB plus 12 digits; government departments use GBGD### and health authorities GBHA###. Northern Ireland post-Brexit issues XI-prefixed numbers with the same body formats. Matching is uppercase letter prefixes as issued by HMRC.

Type: regex
Engine: boost_regex
Confidence: high
Confidence justification: High confidence when keywords such as "VAT number" or "VAT registration" appear nearby. The GB/XI prefix plus fixed digit lengths sharply reduce incidental matches versus bare digit runs.
Jurisdictions: uk
Regulations: UK GDPR, Data Protection Act 2018, VATA 1994
Frameworks: ISO 27001, ISO 27701, SOC 2
Data categories: financial, business-identifier, government-id
Scope: narrow
Risk rating: 6
Platform compatibility: Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Unsupported

Pattern

\b(?:GB|XI)(?:\d{9}|\d{12}|GD\d{3}|HA\d{3})\b

Corroborative evidence keywords

VAT number, VAT registration, VAT No, GB VAT, [object Object], value added tax, belasting, [object Object], Mehrwertsteuer, [object Object], Umsatzsteuer, BTW-nummer, numéro de TVA, Steuernummer, tax number, tax registration, taxe sur la valeur ajoutée, adószám, imposta sul valore aggiunto, intracommunautaire (+53 more)

Proximity: 300 characters

Should match

GB123456789 — Standard 9-digit GB VAT
GB123456789001 — 12-digit branch trader VAT
GBGD001 — Government department GD format
XI123456789 — Northern Ireland XI VAT

Should not match

GB12345678 — Only 8 digits after GB
FR12345678901 — French VAT prefix, not UK
GBABC123456 — Letters in numeric body

Known false positives

Product SKUs or ticket codes starting with GB plus digits in logistics systems. Mitigation: Require VAT/registration keywords within proximity; layer with invoice/tax document context.
IBAN or other GB-prefixed financial strings with different lengths. Mitigation: Fixed length classes (9/12/GD/HA) exclude most IBAN bodies; use IBAN SIT for accounts.

References

Collections

Coverage Phase 1 Priority Identifiers