GDPR and AI: using LLMs safely with UK customer data

The practical view from people who build these systems — not legal advice; for edge cases, talk to a data-protection professional.

The reassuring part

UK GDPR doesn't have a special AI chapter. The same principles apply — lawful basis, minimisation, security, retention, transparency. If your CRM use is compliant, the framework for AI use is familiar; what changes is where data flows and who processes it.

The five things that actually matter

1. Know whether your data trains someone's model. The major API providers (OpenAI, Anthropic, Google) do not train on business API data by default under their commercial terms — but consumer tools have different terms, and this is the classic trap: staff pasting customer records into a free chatbot account. Fix it with a paid workspace, clear policy, and systems that make the safe path the easy path.

2. Data processing agreements. An AI provider handling your customer data is a processor. You need a DPA with them, same as with your email host. The major providers all offer them; a supplier who can't is a red flag.

3. Minimisation is a design decision. An automation that drafts replies doesn't need the customer's full record — it needs the thread and relevant facts. Well-built systems send the minimum useful context per task. This is cheaper as well as safer: smaller context, smaller bills.

4. Retention and deletion flow through. If a customer's data must go, it must go from the AI layer too — including any indexes or embeddings built from it. Ask any supplier: "when I delete a record, what happens in your system?" A good answer is specific.

5. Automated decisions need a human. UK GDPR restricts significant decisions made solely by machine. The design answer is the human approval step — which you should want anyway (here's why). AI drafts, flags and sorts; people decide.

Questions to ask any AI supplier

• Where is the data processed and stored, and under which terms?
• Is any of it used for model training? Show me where the contract says no.
• What's logged, for how long, and who can see it?
• How does deletion propagate?
• Which decisions can the system take without a person?

A supplier who answers crisply has thought about it. One who says "don't worry, it's encrypted" hasn't understood the question.

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