A claim is four steps you take and one HMRC takes. First, check whether your company has to submit a claim notification, because that deadline can end the question before it starts. Second, prepare the technical and cost analysis behind the claim. Third, submit the Additional Information Form before or on the same day as the company tax return — a claim made without it is invalid. Fourth, claim the relief in the return itself, quantified, with computations that agree. HMRC then processes the claim: its published aim is to pay 85% of payable tax credits within 40 days or to make contact within that time.
Step 1: check whether a claim notification is required
For accounting periods beginning on or after 1 April 2023, some companies have to tell HMRC they intend to claim, months before the claim itself. The requirement applies where you are claiming R&D tax relief for the first time, or where your last claim was made more than three years before the last date of the claim notification period. One trap sits inside that test: a claim for a pre-April 2023 period made by amending a return, where the amendment reached HMRC on or after 1 April 2023, does not count as a previous claim. Companies that think of themselves as established claimants are caught by it. That window opens on the first day of the period of account and closes six months after the end of it. HMRC’s guidance is short about the consequence: if you do not notify, the claim is invalid.
There is no late route. The one alternative HMRC offers is to file the R&D claim itself, on the return or as an amendment, so that it is received by the last date of the claim notification period — which for most companies means preparing the whole claim inside six months of the year end. Our guide to the claim notification requirement works through who is caught and who is exempt, and the claim notification deadline checker gives you your own date in seconds. Settle this before anything else. Every later step is wasted if the notification was needed and missed.
Step 2: prepare the technical and cost analysis
Two strands of work, and they run together.
The technical strand identifies each project that sought an advance in science or technology, states what was scientifically or technologically uncertain, and describes how the work set about resolving it. This is the competent professional’s account, not the finance team’s: the Additional Information Form asks for the baseline knowledge in the field, the uncertainties faced and the methods used to overcome them, project by project.
The cost strand traces qualifying expenditure back to payroll records, ledgers and invoices, with each apportionment recorded at the time rather than reconstructed later. What records you need sets out the evidence that holds up when a claim is examined.
Step 3: submit the Additional Information Form
The Additional Information Form has been required for claims made on or after 8 August 2023, and a claim made without one is invalid. It must be submitted before or on the same day as the Company Tax Return, and where both go on the same day, the form has to go first. The accounting period dates on the form have to match the dates on the return.
Order matters more than people expect. Where the return arrives first, HMRC writes to confirm that it is removing the R&D claim from the return, and if that happens close to the last date for amending the return, there may be no time left to make a valid claim. Companies have lost whole periods this way. What goes in the Additional Information Form covers the fields and the detail HMRC expects in each.
Step 4: claim in the company tax return
Claims are made in the Company Tax Return or by amending it. HMRC expects a completed CT600, computations that reflect the claim, and a CT600L where the claim includes the merged scheme R&D expenditure credit or a payable ERIS credit. The amount of relief or credit has to be quantified when the claim is made. An incomplete return, or a claim where the relief is not quantified, is not a valid claim at all.
Reconcile the three documents before filing. Figures that disagree across the return, the computations and the Additional Information Form are among the easiest things for HMRC to spot.
What happens after you file
HMRC’s aim is to pay 85% of payable tax credits within 40 days of receiving the claim, or to make contact about the claim within that time. That aim is HMRC’s, not any adviser’s, and it does not apply to claims made without accurate BACS details or, in exceptional circumstances, made outside the electronic route. Where HMRC thinks a claim may be incorrect, it withholds payment and aims to open an enquiry within 60 days of receiving it. How long it takes to receive an R&D tax credit covers the timing, and what can hold a payment up, in full.
Payment is not approval. HMRC checked around one in six claims in 2023-24, its latest published figure, and it can enquire after paying as well as before. That is the argument for filing a claim built to be read by an inspector: see HMRC R&D enquiries for what a check involves. If you want the procedure settled properly for your own period, talk it through with us.
Sources
- Tell HMRC that you’re planning to claim R&D tax relief — who must submit a claim notification, the three-year test measured to the last date of the claim notification period, the window running from the first day of the period of account to six months after its end, the invalidity of a claim where no notification was made, and the alternative of filing the claim itself by that date.
- Additional information you must submit before you claim R&D tax relief — the form must be submitted before or on the same day as the Company Tax Return, the project information required including baseline knowledge, uncertainties and the methods used to overcome them, and HMRC’s removal of the claim from the return where the return is filed first.
- CIRD182000: additional information requirement — the form is required for claims made on or after 8 August 2023, the accounting period dates must match the return, and a claim without it is invalid.
- CIRD181000: reformed reliefs, claims process — claims are made in the Company Tax Return or an amendment to it, with a completed CT600, computations reflecting the claim and a CT600L for a payable credit; the amount must be quantified, and an incomplete or unquantified claim is not valid.
- CIRD80525: practice note for ISBC and WMBC — HMRC’s aim to pay 85% of payable tax credits or make contact within 40 days, the exclusion of claims without accurate BACS details and non-electronic claims, and the aim to open an enquiry within 60 days where it decides not to pay.
- HMRC’s approach to R&D tax reliefs 2023 to 2024 — 9,700 compliance checks against around 61,000 claims received, the source of the one-in-six check rate.
This page describes the rules as they stood at the review date above, as general information rather than advice on your circumstances. For how that distinction works, see our terms; for an answer on your own facts, talk to us.