Short answer
Most of what HMRC asks for during an R&D enquiry is informal correspondence, and most companies simply provide it. Where HMRC wants to compel a response, it can issue a formal information notice requiring you — or, separately, a third party — to provide information or produce a document that is “reasonably required” to check your tax position. You can appeal most requirements within 30 days of the notice. The significant exception is your own statutory records — the records you are legally required to keep to support your return in the first place — which you cannot appeal being asked to produce.
Applies to
- Schemes
- Merged scheme · ERIS · Legacy SME · Legacy RDEC · All periods
- Periods
- 1 April 2009 onwards
- Claimants
- All
Informal first, formal if needed
Most information exchanged during an R&D enquiry happens through ordinary correspondence — HMRC asks, and you (or your adviser) respond. A formal information notice is the power HMRC falls back on when informal cooperation isn’t forthcoming, when a third party needs to be compelled rather than simply asked, or when HMRC wants the added weight of a formal notice, including the penalty regime that comes with one, behind a request. Receiving a formal notice partway through an otherwise cooperative enquiry is not necessarily a sign the relationship has broken down — HMRC sometimes uses one simply to put a specific request beyond doubt — but it is always worth noticing.
What HMRC can require from you
A “taxpayer notice” lets an officer require you, in writing, to provide information or produce a document, where it is “reasonably required… for the purpose of checking [your] tax position.” In an R&D enquiry, this typically covers the technical narrative and its supporting material, project and cost records, contracts relevant to contracted-out or subsidised R&D questions, and correspondence bearing on when a project started, what was uncertain, and when it was resolved.
There is an important restriction on when a taxpayer notice can be used, once you’ve filed a return for the period in question. It can only be given where either:
- an enquiry into that return is already open and has not yet been completed as it relates to the matter the notice is about, or
- HMRC has reason to suspect that tax may have been under-assessed, or relief may have been or become excessive, for that period.
In other words, HMRC generally cannot use a formal taxpayer notice to go fishing in a filed return with no enquiry open and no stated basis for suspicion. Three further conditions exist in the legislation covering other situations (broadly: capital gains base cost questions, certain PAYE and VAT-related matters, and cases where the taxpayer has asked HMRC to determine their tax position) — these are less commonly relevant to an R&D claim specifically and are not covered in detail here.
What HMRC can require from someone else
A separate power — a “third party notice” — lets HMRC require information or documents from someone other than you, where reasonably required to check your tax position. In an R&D context, this could reach, for example, a contractor, an externally provided worker’s agency, or a customer in a contracted-out R&D dispute, where HMRC wants to test your account of the arrangement against theirs. This happened in a compliance check we defended a few years ago, where HMRC wanted to see the bank records of a claimant’s EPWs to see if their expenses had been paid to the EPW or the agency. Because there were dozens of EPWs across many agencies, we argued it was unreasonable for us to obtain them and negotiated a compromise. The general position is more restrictive than for a taxpayer notice — HMRC generally has to give you a summary of what’s being asked for, and in many cases needs your agreement or tribunal approval first — but the detailed conditions were not researched for this entry and should be checked before relying on the specifics in any live case.
Your right to appeal
You can appeal a taxpayer notice, or any individual requirement in one, by giving written notice within 30 days of the date the notice was given, to the officer who issued it. The tribunal can confirm, vary or set aside the notice or any requirement in it — and its decision is final: there is no further right of appeal against it.
There are two important carve-outs from this right:
- You cannot appeal a requirement to provide information or produce a document that forms part of your statutory records — broadly, anything you are already legally required to keep and preserve under the Taxes Acts or another enactment relating to tax. This matters more than it might look: the general duty to keep and preserve records to support a company tax return (covered in What records do I need to keep to support an R&D tax relief claim?) means a good deal of the material HMRC typically asks for in an R&D enquiry — cost workings, the records behind the additional information form, contemporaneous project evidence — is likely to be a statutory record, and a requirement to produce it is very unlikely to be successfully appealed on that ground.
- You cannot appeal a notice the tribunal has already approved before it was given. HMRC can ask the tribunal to pre-approve a notice, and where it has, the ordinary appeal route is closed off.
Where neither carve-out applies — a request for something you were not required to keep, going beyond what’s reasonably needed to check the claim — an appeal is a genuine option, not just a delaying tactic, and is worth taking seriously rather than defaulting to compliance.
If you don’t comply
Failure to comply with a valid, unappealed (or unsuccessfully appealed) information notice carries its own penalty regime, separate from any penalty for an inaccurate return: an initial penalty, followed by further daily penalties for continued failure, and a separate penalty where information or a document provided in response to a notice is itself careless or deliberately inaccurate. The exact amounts are set by statute and are best confirmed when they might actually apply, since penalty figures are the kind of detail this bank does not restate outside the rate and threshold timeline.
Worked example
Illustrative.
| What HMRC asks for | Is it likely a statutory record? | Realistic response |
|---|---|---|
| The cost workings behind the claimed staff costs | Yes — supports the return | Provide; appealing is very unlikely to succeed |
| A dated note of when a named uncertainty was identified, if one exists | Yes, if it was made and kept as part of the claim evidence; more doubtful if it never existed | Provide if it exists; explain plainly if it does not, rather than manufacture one |
| Internal board minutes not otherwise relevant to the claim, requested speculatively | Arguably not a statutory record and not obviously reasonably required | Consider whether to push back or appeal, rather than comply automatically |
| A letter to a subcontractor asking them to confirm details of a contract, sent as a third party notice | N/A — third party notice, not a taxpayer notice | Respond to your own enquiry as normal; be aware HMRC may be testing consistency with the other side’s account |
Where claims go wrong
- Assuming everything asked for is appealable. In practice, most of the core evidence behind an R&D claim is a statutory record, and the appeal route that exists for information notices generally is not available for it. Time spent contesting a request for statutory records is usually better spent compiling the answer.
- Confusing an informal request with a formal notice, in either direction. Most correspondence in an enquiry is informal and carries no penalty for non-response, but that doesn’t make it optional to ignore — HMRC can always escalate to a formal notice, and a pattern of unanswered informal requests is itself a bad look. Equally, treating an informal request as if it carried the same weight and appeal machinery as a formal notice is a misreading of where you actually stand.
- Missing the 30-day appeal window on a genuinely appealable request. As with the closure notice appeal, the clock runs from the date of the notice, not from when the point is fully thought through.
- Sending third-party correspondence to HMRC without checking it against what the company itself has said. Where HMRC is testing consistency across a supply chain, an unreviewed answer from a subcontractor or customer that doesn’t match the company’s own account can do real damage.
- Producing more than was asked for “to be helpful.” A voluntary answer beyond the scope of the notice is not covered by the notice’s own limits, and can open lines of enquiry that a properly scoped response would not have.
John Mapother
Founder & Director
Last reviewed 2 September 2026