Can your staff paste client details into ChatGPT? It depends whose account it is

If it's a personal account, I'd say no. If it's a business plan your company has set up, usually yes, once you've done some basic paperwork. If it's truly confidential, it's worth asking whether it should go to an outside company at all.

All three can look identical on screen. The difference is in the small print behind the login.

Personal accounts

This means the free version, and also the paid plans sold to individuals. Paying doesn't change which side of the line you're on.

Here's what the big four say:

• ChatGPT. OpenAI says you can stop your chats being used for training on individual plans, with a setting called "Improve the model for everyone". Rate an answer with a thumbs up or down, though, and that whole conversation may still be used.
• Claude. On Free, Pro and Max, you choose whether your chats train its models. Allow it and Anthropic can keep them for up to five years.
• Gemini. With a personal account and the Keep Activity setting on, some chats are read by human reviewers and kept for up to three years. Google's own advice is "don't enter confidential information that you wouldn't want a reviewer to see".
• Copilot. Microsoft's privacy FAQ says personal accounts can opt out of training, and that training doesn't apply to work accounts. It also says that section covers the older app, so check the newer overview if you're on the version released in August.

None of that is sinister, and it's all written down. But each setting belongs to the person using the account, not to you. If someone pastes in a client's contract, you've no way of knowing what their settings were, or even that it happened.

Business plans

Here the company signs up, and the terms are different.

• ChatGPT Business and Enterprise. OpenAI says it doesn't train on this data unless you've opted in, and it will sign a Data Processing Addendum with these customers.
• Claude Team and Enterprise. Anthropic acts as a processor on your behalf, and its Data Processing Addendum comes with the Commercial Terms.
• Gemini with Google Workspace. On licences that include Gemini as a core service, chats and files aren't reviewed by people or used to improve its AI models. Check which edition you're on.
• Microsoft 365 Copilot. Prompts and responses aren't used to train the underlying models.

Why the paperwork matters

I'm not a lawyer, so treat this as a pointer. If an outside company handles personal data on your behalf, the ICO says "there must be a written contract".

That's the real gap with a personal account. A setting in someone's profile is a preference. It isn't a contract between your business and the provider.

The ICO's questions page also has useful answers on AI tools. For a meeting and drafting tool where the provider doesn't use the data for its own purposes, it says you can generally stay on the lawful bases you already have. You should still update your privacy notice, check the output is accurate, and follow the rules on sending data outside the UK.

And when none of that is enough

A business plan doesn't mean your data stays in the building. It still goes to the provider's servers, under a contract. For most small businesses that's fine, and I'd tell you so.

It may not be fine if a client contract restricts who can see their data, or if you handle health, legal or HR records and would rather they never left your hands. Read your contracts before you decide.

That's where running your own comes in. Openly available models now run on a single decent machine, so nothing goes to an AI company at all. They aren't as clever as the very best cloud models, but they do the everyday jobs well: summarising, first drafts, and finding things in your own files.

It's not cheap, though. My setup starts at £2,500, plus the hardware, and memory prices aren't helping. If you just need a safe place for ten people to draft emails, a business plan will usually win.

What to do this week

1. Ask your team what they use. Make it a friendly question, not an inquisition, or you won't get an honest answer.
2. Pick one approved tool and pay for the business plan, so there's a contract.
3. Write a rule that fits on a page. My starting point: nothing with a client's or employee's personal details goes into a personal account, ever.
4. Strip out the names where you can. The ICO suggests considering this before sharing personal data with an AI developer. "Client A owes us £4,000" often does the job just as well.
5. Read your client contracts for anything on third parties or subcontractors, and update your privacy notice.

If you still don't want it leaving the building, tell me what your team uses AI for and what worries you. I'll tell you honestly whether running your own makes sense.