Copilot, ChatGPT or Claude for a UK business on Microsoft 365?

Copilot is the only one of the three sold in pounds and the only one that is an add-on. Microsoft’s UK pricing for Copilot Business, the tier for organisations under 300 users, is £16.10 a user a month on an annual commitment. The full Microsoft 365 Copilot licence used by larger firms is listed between about £23 and £30 a user a month depending on channel and term. Either sits on top of a qualifying Microsoft 365 plan, Business Basic, Standard or Premium, or E3 and E5, and cannot be bought alone. A firm on Business Standard is therefore paying for two licences per head.

Claude Team and ChatGPT Business are each $20 a seat a month billed annually or $25 monthly, about £15 or £19 at today’s rate, before VAT, and stand alone. For a ten-person firm on Microsoft 365 Business Standard, the year looks like this.

Microsoft UK list prices and Anthropic and OpenAI list prices on 24 September 2026, ex VAT. Dollar prices converted at USD 1 = GBP 0.7545.

Copilot’s advantage is not the model, it is the plumbing. It sits inside the applications your staff already have open and it can read what Microsoft Graph knows about them: their mailbox, their calendar, the Teams meetings they were in, the documents in SharePoint they have permission to see. Ask it what was agreed with a client last month and it can find the email thread, the meeting transcript and the proposal without anyone uploading anything. Meeting recaps in Teams alone justify it for people who spend their day in calls.

It also inherits Microsoft’s tenancy: data stays inside your Microsoft 365 boundary, Microsoft’s commitments on not training on customer data apply, and your existing conditional-access and retention policies cover it. For a firm whose IT provider already manages Microsoft 365, that is the lowest-friction way to put AI in front of everyone, and the one an auditor will find easiest to sign off.

Think. Across independent reviews and our own daily use, the underlying models in Claude and ChatGPT produce better long-form writing, better analysis of complex documents and better code than Copilot does, and users notice. The most common complaint from firms that rolled out Copilot alone is that it is excellent at finding things and mediocre at writing them, and that staff drift back to a personal ChatGPT account for anything hard, which is exactly the data-protection outcome the Copilot purchase was meant to prevent.

Claude narrows the integration gap with its Microsoft 365 extension, which puts Claude inside Word and Outlook, and with Projects for shared context. ChatGPT has its own connectors for files and calendars. Neither sees your whole tenancy the way Copilot does, and neither has the meeting recap. But for the person writing the tender, the advice note or the code, the quality difference is the thing they feel every hour.

All three business products commit not to train on your content. Copilot processes inside your Microsoft 365 tenancy, in the region your tenancy lives in, which for a UK firm is normally the UK data centres, and it is covered by the Microsoft data protection terms you already accepted. Claude Team and ChatGPT Business process on their vendors’ infrastructure in the United States under the standard contractual clauses with the UK Addendum, with DPAs available from both, and Anthropic holds ISO 27001, ISO 42001 and SOC 2 Type II.

For most SMEs the difference is administrative rather than legal: Copilot is one fewer processor to record. For a firm with a client contract that requires UK processing, Copilot is the only one of the three that satisfies it out of the box; Claude and ChatGPT can, through AWS Bedrock in London or Azure OpenAI in UK South, as development projects.

Every Microsoft 365 business subscription already includes Copilot Chat at no extra cost: a web-grounded chat assistant, signed in with the work account, with the enterprise data protection that keeps prompts out of training. Firms should switch it on and tell staff about it, because it is the cheapest way to get people off personal ChatGPT accounts. What it does not do is the thing the paid licence is for: it cannot see your mailbox, calendar, Teams meetings or SharePoint files, and it does not sit inside Word, Excel and Outlook. If your staff mostly want a safe general assistant, Copilot Chat plus a handful of Claude or ChatGPT seats for the writers may be the whole answer. If they want their own documents and meetings summarised, that is the paid Copilot.

Copilot is only as good as the tenancy it reads. Three things decide whether the paid licence pays back. Permissions: Copilot shows people whatever SharePoint and OneDrive already let them see, so a firm with years of over-shared folders discovers that fact on day one, and a permissions review belongs before the rollout, not after. Where the documents live: if the firm’s real work sits in a line-of-business system, a shared drive on a server, or personal desktops, Copilot has nothing to find, and the value drops to meeting recaps and email. And meetings: recaps need transcription switched on in Teams, which is a policy decision some firms have not yet taken. Your IT provider can do all three in a week; ask for them as a condition of the Copilot order rather than a follow-up.

Copilot is also normally bought through the same cloud solution provider that supplies the Microsoft 365 licences, on the same annual term, which makes it the easiest of the three for a firm that wants one supplier and one invoice. Claude and ChatGPT are bought direct on a card, which is simpler for a small firm and less tidy for a larger one.

This is the allocation we make when a Microsoft 365 firm asks. It usually ends with Copilot for some seats and Claude or ChatGPT for others, and the combined bill is still under £400 a head a year.

Give five people Copilot and five people Claude or ChatGPT for a month, matched by role, and give both groups the same ten real tasks from your own work: a client email thread to summarise, a proposal to draft, a spreadsheet to interrogate, a meeting to recap, a policy to rewrite. Score the output blind. Then buy on the scores and the licences you already hold, not on the demo either vendor gave you. The whole exercise costs a few hundred pounds in licences and settles a decision most firms otherwise argue about for a year.