The short answer
A UK tax advisory firm should brief an agency on one service line at a time, and put a written never-say list at the centre of the brief. HMRC's guidance says it never authorises phrases such as HMRC approved, and ICAEW's marketing guidance bars advertising that brings the profession into disrepute. The managing partner should agree the list of claims nobody may make before an agency drafts anything.
Key takeaways
- A tax advisory brief is narrower than an accountancy practice brief: one service line, one kind of enquiry, one page.
- The never-say list is the section that decides the engagement, because it fixes what the agency may not claim for the firm.
- HMRC says it never authorises wording such as HMRC approved, so that wording belongs on the list.
- Run a five-test completeness check before the brief goes out, and wait a week rather than send a brief that fails one.
- If the partners cannot agree on one service line, the first spend is on that decision.
The common assumption is that a tax advisory firm briefs an agency the way an accountancy practice does: describe the firm, list the services, ask for a better website. That brief is the one every agency has already read. A general practice sells a relationship that builds over years, so a broad brief can work. A tax advisory prospect in the UK arrives with a specific question, such as how an owner-managed company should take money out or whether a research and development claim is worth making, and the page that answers it is the page that earns the enquiry. A brief listing twelve services asks the agency to write about all twelve, and the result is about none of them. The better brief is one page with six parts, written around one service line, and it spends most of its words on what the firm will not say.
Why the brief is narrower than an accountancy practice's
A tax advisory brief starts from the question a prospect types, not from the firm's service list. Take a fifteen-person advisory firm, invented for this example. Its partners advise on three kinds of work, and each draws a different prospect with a different worry. One brief covering all three gives the agency no way to choose, so it writes the safest sentences it can, and the safest sentences are the ones every competitor already has. A brief covering one service line lets the agency write a page that a partner would recognise as theirs. The wider question of how accountancy-led firms should think about the channel is covered on our page for accountancy practices.
The six parts of the brief
Six parts fit on one page, and each settles a decision the agency would otherwise guess at. The table names who should write each part. Two of the six need a partner who takes the calls, not a marketing contact, because only that person knows what a good enquiry looks like.
| Part | What it settles | Who writes it |
|---|---|---|
| 1. One service line | The question a prospect asks and the single page that answers it | Managing partner |
| 2. The enquiry wanted | A sentence describing a good enquiry and one describing a poor one | The partner who takes the call |
| 3. The never-say list | Claims nobody may make for the firm, with the reason for each | Managing partner, with compliance |
| 4. Approval and evidence | Who signs off a page and what record of it is kept | The firm |
| 5. What the agency may see | Which accounts and systems, and whether any client data is involved | The firm |
| 6. The first-month test | One page, one approval cycle and one measured turnaround | Both sides |
The never-say list
The never-say list is a page of claims the agency may not make for the firm, agreed by the managing partner before any copy exists. Two kinds of claim belong on it. The first is a promise about an outcome: a saving or a refund in a stated number of days. A partner can stand behind a statement about how the firm works. A promise about what a stranger will get is a different matter, and the agency has no way to check it. The second is official endorsement. HMRC's guidance for contractors says that promoters may describe a scheme as HMRC approved when it is not, and its guidance on avoidance schemes aimed at contractors states that HMRC never authorises statements such as HMRC compliant or HMRC approved. Read HMRC's guidance on tax avoidance schemes aimed at contractors and agency workers and Spotlight 29 on misleading claims by scheme promoters before writing the list.
A firm that has no wish to be near that language still needs it written down, because an agency writing quickly will reach for a phrase that sounds reassuring. The professional side matters as well. ICAEW's tax helpsheet on marketing says firms must not bring the profession into disrepute through their marketing, and it lists things an advertisement must not do, including disparaging the services of other firms. The helpsheet says its list is not exhaustive, so read the current ICAEW marketing helpsheet and the rules of the firm's own professional body rather than relying on a summary here. The joint standard Professional Conduct in Relation to Taxation is the wider context for members who advise on tax.
Give each entry a reason in a few words, because an agency that understands why a line is banned will avoid its cousins too. This article does not say what any firm may or may not claim, since that depends on its regulator and its own advice. It says only that the list should exist, be written down, carry a partner's name and be read by the agency before drafting.
Writing the enquiry you want
Describe a good enquiry in a sentence a partner would recognise, and a poor one in another. Without this, the agency will measure the only thing it can see, which is volume. A good enquiry for the invented firm might be an owner of a company who names the decision in front of them and asks whether the firm advises on it. A poor one might be a general request for a tax return, which belongs with an accountancy practice. Writing both down lets the agency shape the page to attract the first and filter the second, and it gives the firm a fair way to judge the agency's work after a quarter.
Ask the agency to price this part separately from the build. An itemised quote shows what is being bought, as argued in what a recruitment agency should pay for a new website, and a supplier unwilling to show the work of qualifying enquiries as a line has probably not planned it.
Before you brief anyone
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Free to your firm. The agency pays us, and only if the relationship works, so we have no reason to favour a supplier that ignores your never-say list.
Get a recommendationApproval, access and the first month
Parts 4 to 6 are logistics, and they decide whether the first month is slow or merely careful. Name the role that signs off a page and the record kept. The same approval-first reasoning, for a firm regulated by the FCA, is set out in what an insurance broker should look for in an agency. On access, start read-only and name the accounts. If any client data could be involved, say so in the brief and stop there, because that is a conversation with the firm's own data protection lead before it is a conversation with an agency.
For the first month, ask for one page and one approval cycle, not a full site. The agency then learns how much comment a partner actually writes, and the firm learns how long approval takes. By the end of the month the agency can quote a turnaround it has measured instead of one it hoped for. How we introduce one specialist, and how the fee works, is set out in how it works.
A completeness check before it goes out
Five tests catch most of what makes a brief fail, and none needs an agency to run. A partner who did not write the brief should read it against the table below. If it fails any test, the cost of waiting a week to fix it is lower than the cost of an agency starting from a guess.
| Test | A pass looks like | A fail looks like |
|---|---|---|
| One line | One service line named for the first three months | Every service the firm offers, in a list |
| The enquiry | A good and a poor enquiry, each in a sentence | “More leads” |
| Never-say | A page of claims with reasons, carrying a partner's name | “We will know it when we see it” |
| Approval | A named role and an expected turnaround | “Compliance will look at it” |
| Access | Named accounts, read-only to start | “Whatever the agency needs” |
What a good agency does with the brief
A good agency answers the brief with questions before it answers with drafts. It asks whether the partner who takes calls has seen its proposed page, and what happens when two partners disagree. It reads the never-say list back in its own words, so the firm can see it has been understood. An agency that sends a polished deck in reply and skips the list has told you where the list will sit in its process, which is nowhere.
When not to hire yet
Do not brief an agency until the partners can agree on one service line and one never-say list. If the partners cannot agree on either, the agency will be asked to settle a dispute the firm has not had yet, and it will settle it badly. That first piece of work costs a meeting. And if the firm only needs an existing page refreshed, a smaller job may do.
Frequently asked questions
What tax advisory firms ask about briefing an agency.
What should a tax advisory firm put in a brief to an agency?
One service line to start with, a plain description of the enquiry the firm wants, a written list of claims nobody may make, the approval route, the access the agency will have and a first-month test. For a UK tax advisory firm the list of claims is the part that matters most, and the managing partner should agree it before any copy is drafted.
Can an agency write about tax savings on a firm's behalf?
An agency can describe what the firm advises on and how it works. Promises about a saving or a result should come from a partner, with the evidence behind them, or be left out. HMRC's guidance says it never authorises phrases such as HMRC approved, so that kind of wording belongs on the never-say list.
Should the first brief cover every service the firm offers?
No. A brief that lists every service asks the agency to write about all of them at once. Start with the one service line where a prospect's question is clearest, run one approval cycle, then add the next. The first month will show how long approval really takes.
Does a tax advisory firm need a specialist agency?
Not necessarily. A specialist saves explanation time, while a general agency can work if the brief is clear and the firm signs off every line. The test is how the agency behaves when a partner strikes a line out, which you can ask about before signing.
How long should the brief be?
One page is enough for the six parts, and a longer document usually means the firm has not yet chosen a service line. If a UK tax advisory practice cannot fit the brief on a page, the missing decision is almost always internal and worth settling before the agency starts.
Sources and useful reading
- GOV.UK, tax avoidance schemes aimed at contractors and agency workers, for the HMRC position that it does not authorise statements such as HMRC approved.
- GOV.UK, Spotlight 29: misleading claims made by tax avoidance scheme promoters, for the examples of claims HMRC treats as misleading.
- ICAEW, tax helpsheet on marketing, for the guidance on not bringing the profession into disrepute and on what advertising must not do.
- ICAEW, Professional Conduct in Relation to Taxation, for the joint standard on the conduct of members who advise on tax.
This article is commercial decision support and is not legal, tax or regulatory advice. It does not say what any firm may claim, and a firm should ask its own regulator and compliance function. The firm and the example enquiries are invented to show the method. The HMRC and ICAEW material is summarised from search results, not from a full reading of each page, so read the current text before relying on it. Sources were located on 19 October 2026.