The professional bodies leave your prices to you, but they expect the basis of your fee to be agreed in writing before the work starts, and that agreement is most of your recovery position. Fixed and monthly fees move any argument from the size of the bill to the scope, which your engagement letter can settle in advance. When the same client's fee keeps getting written down, it's often the price that needs to change, not the chasing.
In this article
The short version
- Nobody in the profession sets your rates, but engagement letters are mandatory and fees should be agreed before work starts.
- Neither CIOT nor ATT will arbitrate a fee dispute, so your engagement letter is your recovery position.
- Fixed and monthly fees move any argument from the size of the bill to the scope, which you can settle in advance.
- A late-information charge in your schedule of services prices predictable extra work before it happens.
- When the same client's fee keeps being written off, the fix is usually the price, not the chasing.
What the professional bodies require
Nobody in the profession sets a rate. The joint engagement letter guidance from ATT, CIOT, ACCA and AAT, updated in March 2026, treats fees as a commercial matter and names the structures in use: time and expenses, fixed fees, monthly fixed fees, contingent or success fees used with care, and fee insurance. Which you use is up to you.
What the bodies do require is the paperwork around your choice. Engagement letters are mandatory. Your covering letter should deal with fees, at least by cross-reference to your terms, and say when they fall due. CIOT and ATT also ask that your client understands the basis of charging before any work starts, that payment terms go to them in writing, and that fees are agreed before you issue fee notes.
Your recovery position comes from the same documents. ACCA's view is that suing a client for unpaid fees is rarely worthwhile without a letter of engagement. If a client disputes the amount, neither CIOT nor ATT will arbitrate, so you've got a conversation and then the courts, with your engagement letter as what you'd rely on in both.
How each fee structure affects recovery
What differs between structures is when your client sees the number, and so what you'll argue about if they don't like it.
| Structure | When the client sees the figure | What a dispute tends to be about |
|---|---|---|
| Time and expenses | After the work, on the fee note | The size of the bill |
| Fixed fee per job | Before the work | Whether something was in scope |
| Monthly fixed fee | Before the work, spread over the year | Scope, and what happens when the work grows |
| Fee in advance | Before the work, paid up front | Refunds if the work isn't delivered |
Time and expenses puts the pricing conversation at the most awkward moment, after your client has their accounts and before they've paid for them. Fixed fees move it to the start and turn any later argument into a question about scope, which your schedule of services can answer in advance.
Monthly fixed fees suit recurring work, including the quarterly cycle MTD for Income Tax has created for sole trader and landlord clients, and they smooth your cash through the year. Where one VAT invoice covers several instalments, each instalment has its own tax point at the earlier of payment or its due date, so a missed month can still leave you with VAT to account for. Take your own arrangement to your VAT adviser.
Fees in advance are allowed by CIOT and ATT, provided the amount is reasonable against the likely fee, the terms and refund circumstances are in your engagement letter before work starts, and you refund anything paid for work you don't deliver.
Scope creep and late information
Fees often leak through out-of-scope work without anyone deciding they should. A client sends a year's receipts in a carrier bag, adds a second rental property halfway through the year or asks you to look over a loan application, and the extra hours go unbilled because nobody wants the conversation.
The joint guidance gives you a way to price the predictable version of that work. It notes that some schedules of services provide for additional fees where information hasn't arrived by the date requested, or where a return has to be prepared in a short period. Written into your letter, with a date and either a figure or a stated basis, it's a price your client agreed to before the work happened, so applying it later shouldn't surprise anyone. Apply it consistently, though. A charge that's never used tends to teach clients that the deadline is soft.
For work nobody could have predicted, a short written note before you start, saying the request sits outside the agreed scope and what it'll cost, does the same job.
When to reprice and when to chase
When you write off time, your client gets a price cut they never hear about. Next year's fee goes out at the same number, the same work turns up and the same amount comes off the bill. A few patterns suggest the problem is your price, not your collection:
- The same client needs the same extra work every quarter, so the scope hasn't caught up with the job.
- A fee note gets questioned every time it lands, usually because the basis was agreed in conversation and never written down.
- Recovery on one service line falls while the work rises, often where a fixed fee set years ago now covers far more.
- Nobody in the practice wants to send a particular client's bill.
The rest of recovery is about how the agreed fee reaches you. A fee collected by direct debit on a date your client signed up to doesn't depend on anyone remembering to pay it, or to chase it. Adfin collects fees by direct debit, including amounts that change from month to month under one mandate, and sends a payment link for card or pay by bank to clients who can't use direct debit. When fees do go overdue, its AI Customer Agents chase over email, SMS and WhatsApp within rules you set, and can add statutory interest to overdue fees from business clients automatically, with grace periods and waivers for clients you'd rather not charge.
Common questions
Do the professional bodies say what an accountancy firm can charge? No. Fees are a commercial matter; the bodies require that your client understands the basis of charging before work starts and that payment terms are in writing.
Can I sue a client for unpaid fees without an engagement letter? You can, but ACCA's view is that it's rarely worthwhile without a letter of engagement in place, and letters of engagement are mandatory in any case.
Will my professional body arbitrate a fee dispute? Not CIOT or ATT, which say they won't arbitrate between a member and a client on the amount of a fee. They expect you to try to settle it by discussion first.
Can I ask for fees in advance? Yes, if the amount is reasonable against the likely fee, the terms and refund circumstances are in your engagement letter before you start, and you refund work you don't deliver.
Can I charge extra when a client sends records late? Yes, if your engagement letter provides for it. The joint guidance notes that some schedules of services include additional fees for late information or rushed returns, with the amount left to you.
Can I charge interest on unpaid fees? For business clients, statutory interest applies at 8% above the Bank of England base rate, currently 11.75% a year. For private clients you need an agreed term, and the joint guidance says interest on fees must meet Consumer Credit Act requirements.
Sources
- ATT - Engagement letters (joint ATT, CIOT, ACCA and AAT guidance) (accurate as of October 2026) https://www.att.org.uk/engagement-letters
- CIOT - Professional Rules and Practice Guidelines (accurate as of October 2026) https://www.tax.org.uk/professional-rules-and-practice-guidelines
- ACCA - Engagement letters (accurate as of October 2026) https://www.accaglobal.com/gb/en/technical-activities/technical-resources-search/2022/January/engagement-letters.html
- GOV.UK - Late commercial payments: charging interest and debt recovery (accurate as of October 2026) https://www.gov.uk/late-commercial-payments-interest-debt-recovery
- Adfin - Payments and credit control for accountants (accurate as of October 2026) https://www.adfin.com/accountants
