How to Write a Letter with AI: UK Guide

Writing a formal letter to your energy company, GP surgery, or council can feel like hard work. Getting the wording right, keeping the tone calm when you are frustrated, knowing what to include. All of that adds up. AI can take most of that weight away.

This guide walks you through using a free AI tool to write letters that get results: energy complaints, NHS requests, council letters, bank queries, and personal notes. Every section includes a ready-to-copy prompt.

What can AI write for you?

AI is good at taking your rough notes and turning them into a polished first draft. It handles structure, tone, and formal language. Those are exactly the bits that trip people up.

Everyday uses for UK adults include:

• Complaining to your energy supplier about a wrong bill or a missed engineer appointment
• Requesting an NHS appointment or writing about a concern with your care
• Raising an issue with your local council about a pavement, bin collection, or planning query
• Asking your bank to explain a charge, close an account, or update your details
• Writing a thank-you letter, condolence note, or a letter to a school about a grandchild

Before you write any complaint, knowing your rights makes the letter much stronger. Citizens Advice has plain English guides on complaints, refunds, and what companies are legally required to do.

Which AI tool should you use?

ChatGPT (free at chatgpt.com), Google Gemini, and Microsoft Copilot all do the job. None require a subscription. A basic letter costs nothing to draft.

If you have never used one before, start with ChatGPT. Our step-by-step guide to ChatGPT walks you through the whole thing in about five minutes.

How to write a good prompt

A prompt is the instruction you type into the AI. More detail means a better draft. The most common mistake I see, after watching many people try this for the first time, is writing too little. They type three words and wonder why the result sounds like a form letter.

A useful prompt tells the AI four things:

• Who the letter is going to (energy company, GP surgery, council)
• What the situation is (a wrong bill, a missed appointment, a broken pavement)
• What outcome you want (a refund, an investigation, a repair date)
• What tone you need (polite and firm, formal, warm)

Compare these two:

Vague: "Write a complaint letter."

Better: "Write a formal complaint letter to my energy supplier about a bill that is far higher than usual. I believe the meter reading is wrong. I want them to check the meter and send a corrected bill. Keep the tone polite but firm."

The second version gives the AI a clear target. You get a much more useful draft in return.

You can also ask for variations: "Give me two versions, one firm and one softer." That is useful when you are unsure how strong to be.

Copy-and-paste UK letter prompts

Replace the parts in square brackets with your own details before pasting into ChatGPT or any other AI tool.

Complaining to your energy company

Copy this prompt and fill in the brackets:

"Write a formal complaint letter to [supplier name], my energy supplier. My bill for [month] shows a charge of £[amount], which is far higher than my usual bills of around £[normal amount] per month. The meter reading used was [reading], and I believe it is incorrect. I want them to check the meter, issue a corrected bill, and confirm in writing within 14 days. Keep the tone polite but firm."

If your supplier does not resolve the complaint within eight weeks, you can escalate to the Energy Ombudsman. Citizens Advice has a template letter for exactly this step.

Writing to your GP or NHS service

For a routine appointment request:

"Write a polite, brief letter to my GP surgery requesting a routine appointment to discuss [health concern]. I am not in immediate distress but would like to be seen within the next few weeks. Keep it clear and respectful."

For a formal NHS complaint:

"Write a clear, factual letter of complaint to the complaints lead at [GP practice or hospital name]. On [date], [describe what happened]. This affected me by [impact, for example a delay in my treatment or unnecessary distress]. I want a written response explaining what went wrong. Do not include legal references or formal legal language. Keep it in plain, polite English."

The Parliamentary and Health Service Ombudsman (PHSO) publishes its own AI prompts to help patients write clear NHS complaints. Their guidance is worth reading before you draft a letter about your care. Our guide to AI in the NHS also explains the complaints process and where AI fits in.

Raising a concern with your council

"Write a short formal letter to [council name] Council about [issue, for example a pothole on [street name] that has been there since [date]]. I want to know when it will be repaired and who I can contact for updates. Keep the letter brief and factual."

Asking your bank about an account

"Write a formal letter to [bank name] querying a charge of £[amount] on my account on [date]. I do not recognise this charge and would like it explained or refunded if it was made in error. My account is with [branch name]. Do not include my real account number here as I will add it before sending. Keep the tone professional."

Personal letters and thank-you notes

"Write a warm, genuine thank-you letter to my neighbour [placeholder name] for [reason, for example collecting my parcels while I was in hospital]. Keep it brief and personal, not too formal."

"Write a short condolence note to [placeholder name], a friend whose [relative] has recently passed away. Keep the note gentle and brief. Focus on the person, not the loss."

What not to put into the AI

The AI does not need your real personal details to write the letter. Use placeholders instead, then replace them in the draft before you send it.

Do not paste in:

• Your full address
• Your NHS number
• Your bank account number or sort code
• Your date of birth
• Any passwords or PINs

Write [my address], [account number], and [NHS number] in your prompt. Add the real details to the final letter yourself, once the AI has done its job.

If you do paste in real details, your conversation may be used to improve the AI system depending on your privacy settings. It is not the same as sending a message to a friend. For a bank account query or an NHS complaint, that is a risk not worth taking when placeholders work just as well.

The Parliamentary and Health Service Ombudsman makes the same point in their own guidance on using AI to fill in their complaint form: "Remove any personal information that could identify you. Add your personal details directly to the complaint form, without sharing them with the AI tool."

For a broader look at what to keep private, read our guide to what not to tell ChatGPT. If you are concerned about how ChatGPT handles your data, our ChatGPT privacy guide covers what you can turn off.

What the NHS says about AI-written complaints

One warning worth knowing, particularly for NHS complaints. Mid Cheshire Hospitals NHS Trust has published guidance noting that AI-generated complaints can sometimes become too complicated, or include legal references that were never asked for. This can slow the complaints process down or mean a letter needs to be resubmitted.

Their advice: keep the letter focused on what happened to you personally, and how it affected you. Plain, direct language gets a better response than formal legal phrasing.

In practice, add one line to your prompt: "Do not include references to any laws or regulations. Keep this in plain English." That small addition makes a real difference to the result.

How to make the letter sound like you

AI drafts are a starting point, not a finished letter. Reading it out loud is the best test I know. If you wouldn't say it that way, rewrite it.

Add one detail that only you know, such as a specific date, a name, or a particular incident. That line makes the letter feel real rather than something produced by a template.

If the tone feels too stiff, tell the AI: "Rewrite the second paragraph to sound less formal." If it feels too casual for a formal complaint, ask for the reverse. You control the final version.

Here is what that looks like in practice. The AI might write: "I am writing to express my dissatisfaction with the service received." That is technically correct but nobody talks that way. Change it to something like: "I am writing because the engineer did not arrive as promised, and I have now been without heating for three days." Specific, plain, and personal. That is the version that gets a response.

Before you send it

• Check every name, date, and reference number is correct
• Replace all placeholders with the real details
• Read it out loud and change anything that does not sound like you
• Remove any section the AI added that is not true or relevant
• Keep a copy of the letter and note when you sent it

Want to get more confident with AI tools in everyday life? The WellWired Academy is a short, jargon-free course that covers letter writing, staying safe online, managing money, and much more. It is designed for complete beginners.