Three names. Every business owner has now heard them. ChatGPT made the news, Microsoft Copilot turned up in a conversation with the accountant, and someone on LinkedIn keeps mentioning Claude. The question on every Tuesday morning call we are getting at the moment is the same: which one should I actually buy for my business?

Hi, I’m Andy from Initial IT. We are a Lichfield-based managed IT and cyber security firm, and a Microsoft Partner. So before we start: yes, we sell Microsoft 365, yes, we set up Copilot for clients, and yes, that creates a small commercial incentive for us to tell you Copilot is the answer. We are going to be honest instead.

ChatGPT vs Claude vs Copilot, three AI assistants compared for UK business owners

Key takeaways

Copilot uses ChatGPT and Claude underneath. Microsoft routes tasks to the model that suits them best. Buying Copilot gives you both, wrapped in Microsoft 365 controls.
For staff use, Copilot is realistically the only credible option. It is the only one of the three that lives inside your tenant and is governed by an admin you employ.
Owners can experiment with all three. Most teams that get this right run two: Copilot for the day job, ChatGPT or Claude for the harder thinking outside Office.
Cost is closer than it looks. Personal tiers all sit between £18 and £25 a month. Copilot looks dearer because it sits on top of a Microsoft licence you probably already need anyway.
Free tiers are never safe for business data. Treat them like a public website. Paid business tiers of all three are fine for normal work.

Here is the 30-second version, the long version, the cost picture, the privacy picture, and a one-paragraph guide for which one you should start with.

The 30-second answer

If your team already lives in Microsoft 365 (email, Word, Excel, Teams) and you want a safe, controlled rollout that uses your business data, start with Microsoft Copilot. If you mostly need a thinking partner for drafting, brainstorming, research and ad-hoc writing outside the Microsoft tools, ChatGPT or Claude. Most UK SMEs end up with two: Copilot for the day job, ChatGPT or Claude for everything else. And if the goal is to roll AI out to staff securely, Copilot is realistically the only option. More on that below.

ChatGPT (from OpenAI)

The most famous of the three. The one your kids and your sales director have probably been using. ChatGPT is best at:

General-purpose drafting, brainstorming and conversational work
Searching the live web (in the paid tiers)
Producing a wide variety of content: emails, marketing copy, summaries, training material
Letting you build small custom assistants (“GPTs”) for specific recurring jobs
Analysing uploaded files (PDFs, spreadsheets, images)

Where ChatGPT is weaker for a business owner:

It does not live inside your Word, Outlook or Excel. You copy and paste between ChatGPT and your work, which is fine for some jobs and awful for others.
The privacy and data residency picture depends on which plan you are on. The Team plan is decent. The free and personal plans should never see anything sensitive.
The free tier uses your prompts to improve the models. Most owners do not realise this until they look.

Claude (from Anthropic)

The quieter one of the three. Claude has built a serious following with developers and knowledge workers who value careful, long-form thinking. It is best at:

Long-form drafting (full reports, blog posts, client proposals) where the output needs to feel measured rather than excitable
Working with very long documents in one go (contracts, transcripts, manuals) without losing the thread
Following nuanced instructions and pushing back when something does not make sense
Code and structured analysis work

Where Claude is weaker for a typical UK SME:

No native Office integration. Like ChatGPT, you are working in a browser tab, not inside Word.
Lower brand awareness in the boardroom, so you may spend more time explaining what it is and why a member of staff is using it.
Team plans require a higher minimum seat count, which can feel awkward for a small firm.

If we are being honest, Claude is what a lot of our own behind-the-scenes drafting runs on. It is calm, careful, and good at the kind of writing you would not be embarrassed to send a client. But it is the hardest of the three to plug straight into a Lichfield accountancy practice.

Microsoft Copilot (for Microsoft 365)

A point most people miss. Microsoft Copilot is not a single model. It is an orchestration layer that calls models from OpenAI (the family behind ChatGPT) and from Anthropic (the family behind Claude). Microsoft picks which model handles which task based on what gives the best result. When you pay for Copilot, you are getting the underlying intelligence of both ChatGPT and Claude, wrapped in Microsoft’s enterprise controls and dropped straight into your Office tools.

The newest of the three to most business owners, and the most misunderstood. Copilot is best at:

Living inside the tools your team already uses: Outlook, Word, Excel, Teams, PowerPoint, OneNote, SharePoint
Drafting using your actual business content, your emails, your files, your meeting transcripts, securely, with proper enterprise controls
Catching you up on a Teams meeting you missed, drafting a reply to an email thread, building a PowerPoint from a Word doc
Working with your data without that data ever leaving your tenant or being used to train anyone’s model
IT control: admins can lock down what data Copilot can see, by department, by site, by user

Where Copilot is weaker:

The raw conversational quality is below ChatGPT and Claude. It is good, not best in class.
Without a tidy Microsoft 365 tenant, results are mixed. Bad SharePoint hygiene shows up as bad Copilot answers. We see this a lot in tenants we inherit.
The licence requires Business Standard or Premium underneath, which catches a lot of smaller firms by surprise on the costings.

Cost, in real numbers

Per user per month, UK list prices at the time of writing:

ChatGPT Plus (personal): around £20
ChatGPT Team: around £25 per seat (minimum two seats, annual billing)
ChatGPT Enterprise: pricing on application, typically from around £60 per seat
Claude Pro (personal): around £18
Claude Team: around £25 per seat (minimum five seats)
Microsoft Copilot for M365: £24.70 per user per month, on top of Business Standard (£11.70) or Business Premium (£21.72)

Read that last line again. Copilot is the one that needs the underlying licence first. For a 20-person business already on Business Premium, that is £21.72 + £24.70 = £46.42 per user, per month, for the people who get Copilot. You do not need to license it for everyone.

The privacy and data question

This is the one your finance director will ask. The honest summary:

Microsoft Copilot for M365: prompts and data stay inside your tenant. Microsoft does not use them to train models. UK data residency is available. The clearest enterprise-safe option of the three.
ChatGPT Team and Enterprise: data is not used to train models. Workspace privacy controls are in place. The free and Plus tiers are different, assume anything you type there could be used to improve the models.
Claude Team and Enterprise: same picture as ChatGPT Team. Anthropic states clearly that customer content is not used for training. The personal plan is more relaxed.

Rule of thumb: never type customer names, financial figures, contracts or anything sensitive into the free tier of any of these tools. The paid business tiers are fine for normal work. If you are in a regulated industry (legal, financial, healthcare), the rules go up a notch and we would steer you towards Copilot first.

Which one should you start with?

A short decision guide that covers about 80% of the businesses we talk to:

You run on Microsoft 365 and want a safe, supervised rollout? Copilot first. Add ChatGPT or Claude later for the team members doing a lot of writing outside the Office tools.
You barely touch Office and live in Google Workspace? ChatGPT or Claude. Copilot does not fit your stack.
You have a small team doing a lot of marketing, content or strategy writing? Claude for the writing, ChatGPT for the brainstorming and image generation. Skip Copilot until you have sorted the M365 tenant.
You are a one-person business? Start with ChatGPT Plus or Claude Pro at £18 to £20 a month. Do not over-engineer it.

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60 minutes covering ChatGPT, Claude and Copilot side by side. Real examples, what to safely roll out first, and the data and policy questions you have not thought of yet. No sales pitch.

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Most teams end up running two, but with one important caveat

This is the part vendors do not enjoy hearing. The honest pattern we see across our client base is two tools per knowledge worker: one inside Microsoft 365 (Copilot) for the day job, and one outside it (ChatGPT or Claude) for drafting, research and the harder thinking.

That works for an owner or a director making their own personal productivity choice. The moment you roll AI out to your wider team, the security calculation changes, and it is not subtle.

For staff use across a UK SME, Copilot is realistically the only credible option.

It is the only one of the three that runs inside your Microsoft 365 tenant, respects your existing data and access controls, and is governed by an admin you employ. The free and personal tiers of ChatGPT and Claude on a staff laptop create data-leakage and Cyber Essentials problems that the business, not the staff member, ends up paying for. The team tiers help, but only if they are procured and licensed by IT, not bought on a personal card and reimbursed.

Put simply: business owners can experiment with all three. Staff should only have AI tools that IT can see, control and audit. That, today, is Copilot.

The productivity payback is real when it is rolled out properly. The disappointment we hear most often is from businesses who skipped that last bit.

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Frequently asked questions

Which is cheapest for a UK business?

The personal tiers of all three sit between £18 and £25 a month per seat. Copilot looks more expensive at £24.70 but only because it sits on top of a Microsoft licence you already have for other reasons. The cheapest credible starting point for a single business owner is Claude Pro at around £18 or ChatGPT Plus at around £20.

Can I run more than one in the same business?

Yes, and most teams that get this right end up doing exactly that. Copilot inside Microsoft 365, ChatGPT or Claude for everything else. Pick one per person based on their actual day-to-day work, and remember the staff-security point above: anything used by your team should be procured and governed by IT.

Is it safe to put real client data into any of these?

In the paid business tiers (ChatGPT Team or Enterprise, Claude Team or Enterprise, Copilot for M365), yes, with sensible rules in place. In the free or personal tiers, no. The Cyber Essentials and ISO 27001 view is to treat the free tiers like a public website.

Does Copilot use my business data to train Microsoft’s models?

No. Microsoft is explicit about this. Your prompts, your files and your business data stay inside your tenant and are not used to improve the underlying model.

If Copilot uses ChatGPT and Claude under the hood, why not just buy those directly?

Because Copilot wraps those models in Microsoft 365 enterprise controls: tenant-level data residency, conditional access, sensitivity labels, audit logs and admin governance. ChatGPT and Claude bought directly do not give you those things. You are paying Microsoft for the wrapper, not just the model.

Which is best for a law firm or accountancy practice?

Almost always Microsoft Copilot first, because the client confidentiality and data residency picture is cleanest, and because partners already live in Outlook and Word.

We are already paying for ChatGPT. Should we cancel it and switch to Copilot?

Not necessarily. Lots of owners end up keeping ChatGPT for personal use, with Copilot rolled out across the team. The right answer is to look at who uses what, how often, and how much time it saves them, and then decide.

Where to go from here

If you are weighing this up for your own business, the free AI webinar is the fastest way to see all three in context and ask the questions you have not yet thought of. We also run paid AI strategy and rollout work for businesses ready to do this properly, but the webinar is genuinely free, genuinely useful, and genuinely no sales pitch.