R&D tax relief
The adviser handling your R&D claim has stopped replying
Emails go unanswered, calls don't get returned, and it's been long enough that something is clearly wrong. This is a genuine, recurring problem in a market with a lot of smaller and newer firms, and there's a fairly predictable set of things to check before deciding what to do next.
First, don't assume the worst
Silence isn't always a collapse
Not returning calls doesn't automatically mean the firm has gone under. Plenty of R&D advisers are small operations (a handful of people or fewer), and a single busy period, a staff departure, or a change of priorities can produce exactly the same silence as something more serious. What matters is working out which one it is, and doing that quickly, because a claim sitting unattended has real deadlines attached to it regardless of why the adviser has stopped responding.
Why this happens more here than in most professional services
A market with a lot of smaller, newer firms
R&D tax relief attracted a wave of firms built specifically around it over the last several years, many of them small, contingency-fee operations rather than established accountancy practices with decades of institutional continuity. When compliance activity tightens, as it has, or when a firm's own commercial model comes under pressure, smaller firms are the ones most likely to fold quietly, deprioritise existing clients, or simply stop being reachable. It isn't a reason to avoid the whole market, but it is a reason to check status rather than assume it.
What to actually check first
Working papers, filing status, and who else was named
Three things are worth establishing before anything else:
- Whether the claim was actually filed. If the Additional Information Form was submitted and the claim went in with the Company Tax Return, the position is very different to a claim that was still being drafted when the adviser went quiet. See what the Additional Information Form requires for what that submission looks like.
- Who holds the working papers. The technical narrative, cost breakdown and supporting evidence are the company's material, and a company is entitled to ask for them back regardless of how the relationship ends.
- Whether the adviser was named as agent on the form. That matters if the claim later goes into an enquiry and HMRC is corresponding with an agent who's no longer reachable.
Worth checking directly with HMRC: if you're not sure whether a claim was actually filed, or whether an Additional Information Form went in, that's confirmable without needing the adviser's cooperation. Don't rely solely on what you were last told, especially where the last update is more than a few weeks old.
Timed checklist
What to do, and by when
Silence is easier to deal with once it has a timetable. The stages below run from the day you decide to act to handing the claim to someone new. The pace is our suggestion, not an HMRC rule; the dates that actually bind you are in the table after it. You can download the checklist as a plain-text file with tick boxes and spaces for your own dates, to print or keep with the claim papers.
Short on time? If any date in the fixed dates table falls within the next eight weeks, do not wait out these stages. Do the Companies House and HMRC checks today and start on a replacement straight away.
Today
Write down where things stand and send one clear chase
- Note the date of the last reply you actually received, and what it said. Not the last time you chased. Everything after that date is the silence you are measuring.
- List the accounting periods the claim covers and their end dates. Every fixed date in the table below is worked out from these, not from anything the adviser tells you.
- Send one written chase to every contact you have for the firm, named people and the general inbox. Ask three specific things: which forms were filed and when (claim notification, Additional Information Form, Company Tax Return), with the reference from HMRC's confirmation email for the first two; please send the working papers; are you still acting for us. Give a reply-by date five working days away.
Within 3 working days
Check what you can see without the adviser
- Look the firm up on Companies House Find and Update. It is free and shows company status, filing history, current and resigned officers and any insolvency information. If the firm is in liquidation, administration or dissolved, this is a different problem: see our page on an adviser firm that has collapsed (establishedfinance.co.uk/rd-adviser-collapsed/).
- Search your own inbox for HMRC confirmation emails. HMRC emails a confirmation with a reference number when a claim notification form or an Additional Information Form is received. If the adviser submitted them, the email may have gone to the adviser, so ask for it in writing.
- Check which agents are authorised for Corporation Tax in your business tax account. Manage account, then Add, view or change tax agents. This tells you who HMRC will currently talk to about the company.
By day 7 with no reply
Confirm filing status with HMRC directly
- Call the HMRC Corporation Tax helpline with the company's 10-digit UTR to hand. Ask whether the Company Tax Return for each period has been received and whether it includes an R&D claim. The number and hours are in the sources section below.
- Read the engagement letter again. Look for the notice period, what happens to fees on unfinished work, who holds the working papers, the complaints route and any professional body the firm says it belongs to.
By day 14
Put the request on formal footing and start looking
- Send a formal written request for the working papers and all HMRC correspondence, with a date. The technical narrative, cost workings and supporting evidence were prepared for the company. Say that you intend to instruct someone else if you have not heard by that date.
- If the engagement letter names a professional body, note its complaints route. Use it if the papers are withheld, not as a first step.
- Shortlist a replacement adviser. Our adviser register is checked against Companies House and published terms rather than marketing copy.
By day 21 to 30
Hand over, unless things have already moved
- Instruct the replacement and give them this checklist, the dates table and whatever papers you hold. They will need authorising for Corporation Tax before HMRC will deal with them.
- Remove the old adviser's Corporation Tax authorisation once the new one is in place. Business tax account, Manage account, Add, view or change tax agents, Corporation Tax, manage agents, remove.
The dates that don't move
Whatever the adviser is or isn't doing, these run from your accounting periods and filing dates. Work each one out for every period the claim covers.
| Date | Applies to | The window | If it's missed |
|---|---|---|---|
| Claim notification | Periods beginning on or after 1 April 2023, where the company is claiming for the first time or its last claim was made more than 3 years before the end of the notification period | From the first day of the period of account to 6 months after its end | The R&D claim for that period is invalid |
| Additional Information Form | Every R&D or expenditure credit claim | Before, or on the same day as, the Company Tax Return (CT600). If the same day, the form goes first | HMRC will not accept the claim and writes to say it will remove it from the return |
| Company Tax Return filing | Every company | 12 months after the end of the accounting period | Late filing penalties |
| Making, amending or withdrawing the R&D claim | Periods of account of 18 months or less | Up to the last day of the 2 years beginning with the last day of the period of account | The claim can only be made late at HMRC's discretion |
| HMRC enquiry window | A return delivered on time by a company that is not a member of a large group | Notice of enquiry can be given up to 12 months from the day the return was delivered | Not a deadline for you: it is how long HMRC letters about the claim may keep arriving, so someone must be reachable for them |
If you're not sure whether notification applies to a period, the notification deadline checker works out the exact date from your own inputs, and the three-year rule explains the claim history test. All of the deadlines together are on the R&D claim deadlines calendar.
Sources for the checklist
Fixed dates and HMRC details checked against these on 23 September 2026:
- Claim notification: gov.uk, tell HMRC that you are planning to claim R&D tax relief
- Additional Information Form: gov.uk, submit detailed information before you claim R&D tax relief
- Company Tax Return filing: gov.uk, Company Tax Returns
- Making, amending or withdrawing the R&D claim: Finance Act 1998, Schedule 18, paragraph 83E
- HMRC enquiry window: Finance Act 1998, Schedule 18, paragraph 24
- Companies House Find and Update (free company status, officers, filings, insolvency information)
- HMRC Corporation Tax helpline: 0300 200 3410, Monday to Friday 8am to 6pm, closed bank holidays
- gov.uk, change or remove your tax agent's authorisation
Not tax advice. Your own facts, such as a long period of account or membership of a large group, can change a date.
Registered advisers versus unregistered ones
Registration gives the relationship a formal shape
Advisers who interact with HMRC on a client's behalf now fall under a formal registration requirement under section 223 of the Finance Act 2026 (Part 7): an unregistered adviser may not interact with HMRC unless an exception in Schedule 20 applies. A registered adviser going quiet is a different situation to an unregistered one. There's a formal standing attached to the relationship, and HMRC's own dealings with them run through that registration. It doesn't solve the practical problem of an unresponsive firm, but it does mean the relationship has a documented shape to it rather than being entirely informal.
Finding who's actually still active
Don't just search again from scratch
If the claim needs picking up, whether that's finishing preparation, responding to HMRC, or simply confirming what's already been filed, our adviser register is a starting point. It's checked against Companies House and published terms rather than built from marketing copy, which helps when the firm you already trusted has stopped being reachable.
Decision helper
Alternatives and limitations
If the firm has closed, or an enquiry is open
If a quick Companies House check shows the firm has actually ceased trading or entered liquidation or administration, that's a distinct situation with its own steps: see the adviser firm has collapsed. And if the silence is on an open HMRC enquiry, time matters more than usual: see an HMRC enquiry has opened.
Talk it through
Need another perspective?
Describe where things stand in a sentence or two, and we'll tell you whether it's something we can help with. There's no charge for this.
Thank you. It's with our team now.
A person reads every enquiry and we'll come back to you with what we think the right next step is. No obligation at any point.
What happens next
- A person on our team reads it. A sentence or two is enough to start.
- If we can help, we may introduce you to a provider and tell you who they are.
- No charge and no obligation at any point. You decide whether to go further.
Adam Parker
Founder of Muswell Rose Consulting Ltd, which trades as Established Finance · former Managing Director of Penny, an invoice finance business, working in mortgages, commercial finance and fintech lending since 2010 (career history).
Last reviewed:
Practical questions
Before you get in touch
What information do I need?
To start, just a description of what’s actually happening in the business. If it progresses, the provider will ask for the usual things: recent accounts, a sense of turnover and trading history, and details of the specific need.