AI glossary

Special category data

Also called sensitive personal data, special categories of personal data.

Special category data is personal data that UK GDPR Article 9 protects more strictly: racial or ethnic origin, political opinions, religious or philosophical beliefs, trade union membership, genetic data, biometric data used to identify someone, health, and sex life or sexual orientation. Using it needs a lawful basis and a separate condition.

Think of it as

The locked drawer in the filing cabinet, with a signing-out book.

Why it matters at work

Putting it into an AI tool usually needs an approved tool and often a DPIA. In the course’s tramlines, a named person’s health information is amber only in a tool approved for exactly that, and red anywhere else; criminal offence data has its own rules.

Sources

UK GDPR Article 9: processing of special categories of personal data (opens in a new tab) legislation.gov.uk, read 29 October 2026.
What is special category data? (opens in a new tab) Information Commissioner’s Office, read 29 October 2026.