Managing scope creep and out of scope work

Q: How can you spot scope creep early?

Compare every new request with the schedules. Staff answering the phone should know what the client's letter covers, or where to look. Watch time against fee. ICAEW's fee information helpsheet notes that time records are a management tool rather than a justification for a fee, but a job running well over budget is usually the first sign of unagreed work. Treat life events as triggers. A property sale, new trade, incorporation, separation or move abroad usually means new services. Review the letter regularly. ICAEW's March 2026 practice guidance says engagement letters should be reviewed ideally each year or whenever the scope of work changes, and identifies an ambiguous scope as a frequent pitfall, whether through not being explicit about what is included or not stating what is outside.

Q: How should additional work be agreed?

Name it. Tell the client promptly that the request falls outside the current engagement. Price it or state the basis. Give a fixed fee, an estimate or the hourly basis, in writing. Get agreement before starting. An email reply confirming the fee is better than nothing; a signed additional schedule or updated letter is better still. Decide whether it is recurring. One off work can be covered by a short letter; recurring work belongs in a revised engagement letter. Bill it separately. Describe the additional work on the invoice so it can be matched to what was agreed.

Q: How might this work with a typical client?

Illustration only. A sole trader pays £150 a month for annual accounts and a tax return. In June he mentions he sold a rental flat in May. Capital gains tax reporting is not in his letter. The manager replies the same day explaining that the 60 day property return is a separate service, quotes £400, and attaches a one page additional schedule. The client signs it electronically; the return is filed on time and invoiced separately. At the next annual review, the letter is updated because he now has no rental income but has started selling online, which changes the services needed. Without the schedule, the firm would be choosing between writing off the time and billing a fee the client never agreed, with the dispute then turning on what was reasonable.

Scope creep is work the client asks for, or simply expects, that the engagement letter does not cover. The fix is to define the scope tightly at the start, recognise out of scope requests when they arrive, and agree the extra fee in writing before doing the work. ICAEW’s Code of Ethics requires the basis of fees to be explained in writing and any fee above a quote or estimate to be explained.

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What does scope creep look like in an accountancy practice?

It rarely starts with a large request. Typical examples are:

a bookkeeping clean up before the year end accounts can be prepared, because records arrive incomplete;
answering an HMRC compliance check letter under an annual accounts and tax return fee;
a capital gains tax 60 day return after a client sells a second property;
quarterly updates once a client comes within Making Tax Digital for Income Tax;
identity verification and filing at Companies House for directors and people with significant control;
ad hoc advice by phone or email on a remortgage, a new hire or an overseas move.

ICAEW’s engagement letter templates now treat several of these as separate services with their own schedules, including identity verification, filing company accounts, Making Tax Digital and capital gains tax 60 day returns. That is a useful signal: if a service has its own schedule in the template, it should have its own line in your letter.

Why is out of scope work a risk and not just lost income?

ICAEW’s TECH 09/15BL on managing professional liability recommends setting out clearly the services to be provided, excluding tasks that will not be undertaken where uncertainty might otherwise arise, and monitoring the tasks agreed during the engagement. It also suggests checking that the description of work in invoices matches the engagement letter, any agreed changes and the work product.

The reason is evidential. If a dispute arises over advice given informally, the firm will want to show what it agreed to do and on what terms, including any liability cap. Work drifting outside the letter weakens that position. Extra work can also take the firm into areas where it lacks the necessary expertise; the Code’s principle of professional competence in R113.1 applies whether or not the work is billed. See taking on work outside your expertise.

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How can you spot scope creep early?

Compare every new request with the schedules. Staff answering the phone should know what the client’s letter covers, or where to look.
Watch time against fee. ICAEW’s fee information helpsheet notes that time records are a management tool rather than a justification for a fee, but a job running well over budget is usually the first sign of unagreed work.
Treat life events as triggers. A property sale, new trade, incorporation, separation or move abroad usually means new services.
Review the letter regularly. ICAEW’s March 2026 practice guidance says engagement letters should be reviewed ideally each year or whenever the scope of work changes, and identifies an ambiguous scope as a frequent pitfall, whether through not being explicit about what is included or not stating what is outside.

What do the ethical rules require on additional fees?

The ICAEW Code of Ethics, applying from 1 July 2026, sets out the requirements in section 330:

R330.4: explain the basis on which fees will be calculated and give an estimated initial fee where applicable, at the earliest opportunity.
R330.5: give fee quotes or the basis of fees in writing before the engagement begins or as soon as possible after it starts, normally in the engagement letter.
R330.7: do not mislead clients about the basis of fees for current or future work.
R330.4B.2: if a fee exceeds a previous quote or estimate, explain the reason for the excess and how it was calculated.
R330.4B.1: if the client asks for a fee breakdown, provide one with enough detail to show how the fee was calculated.

ICAEW’s fee information helpsheet adds practical guidance. A fixed fee will be expected to be honoured, so the firm must be clear what the fixed fee covers, ideally in writing. Where it becomes apparent that a quote or estimate will be exceeded, the firm should tell the client in advance, try to give a fresh estimate and seek consent to continue. Monthly standing orders can create an expectation that everything is included, so the terms of those payments should be explicit.

What happens legally if no price was agreed for the extra work?

For a business client, section 15 of the Supply of Goods and Services Act 1982 implies a term that a reasonable charge will be paid where the contract does not fix the price or how it is to be determined. For a consumer, section 51 of the Consumer Rights Act 2015 implies that the consumer must pay a reasonable price, and no more. In both cases what is reasonable is a question of fact, which is exactly what fee disputes argue about.

Consumer clients have further protection:

Section 50 of the Consumer Rights Act makes binding anything said or written to the consumer about the service that the consumer takes into account, so a casual “that will be included” can become a contract term.
Regulation 40 of the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 says no payment is due in addition to the remuneration agreed for the main obligation unless the consumer gave express consent before becoming bound; a pre ticked box does not count.
Where new terms are agreed with a consumer at a distance or away from the firm’s premises, ICAEW notes that the client will in most cases have a right to cancel within a set period, usually 14 days, and must be told about it.

How should additional work be agreed?

Name it. Tell the client promptly that the request falls outside the current engagement.
Price it or state the basis. Give a fixed fee, an estimate or the hourly basis, in writing.
Get agreement before starting. An email reply confirming the fee is better than nothing; a signed additional schedule or updated letter is better still.
Decide whether it is recurring. One off work can be covered by a short letter; recurring work belongs in a revised engagement letter.
Bill it separately. Describe the additional work on the invoice so it can be matched to what was agreed.

How might this work with a typical client?

Illustration only. A sole trader pays £150 a month for annual accounts and a tax return. In June he mentions he sold a rental flat in May. Capital gains tax reporting is not in his letter.

The manager replies the same day explaining that the 60 day property return is a separate service, quotes £400, and attaches a one page additional schedule.
The client signs it electronically; the return is filed on time and invoiced separately.
At the next annual review, the letter is updated because he now has no rental income but has started selling online, which changes the services needed.

Without the schedule, the firm would be choosing between writing off the time and billing a fee the client never agreed, with the dispute then turning on what was reasonable.

What mistakes make scope disputes worse?

Issuing a template letter without tailoring it, which ICAEW identifies as a common pitfall.
Agreeing extra work by phone and recording nothing.
Billing a large catch up fee at year end with no earlier warning, which breaches the spirit of the requirement to explain fees exceeding an estimate.
Assuming a signed letter from several years ago still describes the relationship.
Withholding papers in a fee dispute without checking the rules on liens over client records.

Solar Protect runs fee protection schemes for accountancy and bookkeeping practices. See how our accountant schemes work or read fee protection schemes for accountants.

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Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.