pii.national_id_gb
A UK National Insurance number appears in the free text.
What it looks at#
Two letters, six digits and a suffix letter A-D (AB123456C), optionally printed in
pairs (AB 12 34 56 C) and in either case. HMRC’s published exclusions apply: the first
letter is not D, F, I, Q, U or V; the second is not D, F, I, O, Q,
U or V; and the prefixes BG, GB, KN, NK, NT, TN and ZZ are never issued.
There is no check digit and no keyword is required, because the layout with those
exclusions is distinctive; a longer alphanumeric run containing it does not match.
Why it matters#
The National Insurance number identifies a person to HMRC and the Department for Work and Pensions, and is requested in employment and benefits fraud.
What to do#
High severity. Redact it and check why it reached a free-text field.
Example#
curl -s -X POST https://api.stormdoor.dev/v1/pii \
-H "Authorization: Bearer sk_live_..." \
-H "content-type: application/json" \
-d '{"text":"NI number: AB 12 34 56 C"}'The response carries one pii.national_id_gb finding.