Step 0: decide honestly whether there is a claim
Everything downstream is wasted if the answer here is no. The work must seek an advance in science or technology and resolve real uncertainty, judged through a competent professional’s eyes. The full test is on what counts as R&D, and the company-level conditions on who qualifies. If the honest answer is no, stop; that outcome is covered without euphemism on when you do not qualify.
Step 1: the claim notification window
First-time claimants, and companies whose last claim is more than three years back, must notify HMRC of the intention to claim within a window ending six months after the end of the period of account. Miss it and the claim is invalid before it exists. Dates, mechanics and the traps: the claim notification form.
Step 2: evidence and the competent professional
Gather what exists before creating anything: project plans, tickets, test results, design notes, emails, timesheets. HMRC recommends keeping records from the beginning of the project and, specifically, a written copy of the competent professional’s opinion with supporting reasoning. If records are thin, fix the process now for the current year while reconstructing the past honestly. What good looks like: record-keeping.
Step 3: identify qualifying costs
Map spend into the statutory categories: staff, externally provided workers, contracted-out R&D, consumables including power, software, data and cloud. Apply the apportionments person by person and the 65% restrictions where they bite, and respect the overseas exclusions. The categories and their traps: qualifying costs, with deep pages on staff, subcontractors and agency workers, overseas costs and the PAYE cap.
Step 4: write the technical narrative
The project descriptions must show the baseline, the advance sought, the uncertainties and the systematic work, with the qualifying boundary drawn where the uncertainty starts and ends. Method and structure: the technical narrative.
Step 5: the Additional Information Form
Mandatory for every claim, one per accounting period, submitted before or with the return, naming the responsible senior officer and every agent involved. Return first means rejection. Detail: the Additional Information Form.
Step 6: the Company Tax Return
The claim is made in the return itself, with the R&D figures in the relevant boxes. Per HMRC’s guidance, an X in box 656 confirms a claim notification has been submitted, and box 657 confirms the Additional Information Form has gone in. The CT600L supplementary pages apply, both for expenditure credit claims and for ERIS payable tax credit claims. Once filed, the claim exists; payment, where due, follows processing, and payment is not approval.
Deadlines, and claiming for past years
Two clocks run on every claim. The notification clock, where it applies, closes six months after the period of account ends. The claim clock allows a claim to be made, amended or withdrawn up to two years from the end of the period of account, or 42 months from its start where the period exceeds 18 months. A past year can therefore still be claimable, but for post-April-2023 periods only if the notification position allows it. Corrections in the other direction, claims that were too high, have their own machinery: amending a past claim.
Doing it yourself versus using an adviser
Every step above is open to the company itself, and HMRC’s process is built for it. The honest decision framework, including when DIY is sensible and when advice earns its fee, is on do you need an adviser, with how to choose one and what fees are reasonable alongside it.
- HMRC, Make a claim for R&D tax relief on your Company Tax Return, gov.uk
- HMRC, Additional information you must submit before you claim R&D tax relief, gov.uk
- HMRC, Tell HMRC that you're planning to claim R&D tax relief, gov.uk
- HMRC, CIRD81800 (time limits for claims), Corporate Intangibles Research and Development Manual, gov.uk
Frequently asked questions
How long does a claim take to prepare properly?
For a company with reasonable records, typically a few weeks elapsed: interviews with the technical leads, cost analysis, drafting and review. The elapsed time is driven by evidence-gathering, which is why starting from good records changes everything.
How long does HMRC take to pay?
HMRC processes most payable claims within weeks, but processing is not approval: a paid claim can still be checked afterwards. Build timelines on filing dates, not hoped-for payment dates, and never spend the credit before it clears.
Can we claim for previous years?
Generally a claim can be made or amended up to two years from the end of the relevant period of account, with the claim-notification rule limiting first-time and lapsed claimants for periods from April 2023. Older years than that are usually gone; the disclosure route exists for corrections, not late claims.
Do we need an adviser to do any of this?
No. Every step on this page can be done by the company itself. Whether that is sensible for you is a genuine question, answered honestly on its own page.