Overview

• On July 21, HMRC posted on X warning that sharing NI numbers online can expose individuals to identity theft and should only be done with authorised bodies.
• The advisory highlights that NI numbers are unique lifelong identifiers assigned before age 16 and consist of two letters, six digits and a final letter.
• Only designated organisations—such as HMRC, employers, the Department for Work and Pensions, local councils and approved financial service providers—are permitted to hold a person’s NI number.
• The HMRC app enables users to store their NI number securely and access tax codes, income history, benefit details and other records via PIN, fingerprint or facial recognition.
• People without a UK address or those who have forgotten their NI number are directed to HMRC’s guidance for recovering lost numbers.