What Are R&D Tax Credits in the UK? Everything Businesses Need to Know
Research and development tax credits are one of the most valuable — and most underused — forms of government support available to UK businesses today. HMRC pays out more than £7 billion in R&D relief each year, yet thousands of eligible companies never submit a claim, often because they wrongly assume their work does not qualify. Whether you run a manufacturing firm experimenting with new production processes, a software house building bespoke tools, or a food company developing novel recipes, the chances are that some of your activity qualifies.
This guide explains how R&D tax credits work, who is eligible, what costs you can include, and how to put together a claim that stands up to scrutiny.
What Are R&D Tax Credits and How Do They Work?
R&D tax credits are a UK government incentive that allows companies to reduce their corporation tax bill — or, if they are loss-making, to receive a cash payment — in recognition of spending on innovation. The scheme is administered by HMRC and is available to companies of all sizes, across almost every sector.
The relief works by identifying qualifying R&D expenditure and applying an enhanced deduction (or a direct tax credit) against your corporation tax liability. The practical effect is straightforward: a portion of what you spent on innovation comes back to your business as either a lower tax bill or a cheque from HMRC.
Crucially, HMRC's definition of R&D is broader than most business owners realise. It is not limited to laboratories or formal research programmes. Any project that seeks to achieve an advance in science or technology by resolving a scientific or technological uncertainty can potentially qualify. That includes custom software development, process optimisation, product testing, and even failed experiments.
The Merged Scheme: What Changed in April 2024?
The R&D landscape changed significantly from 1 April 2024, when HMRC merged the two existing frameworks — the SME scheme and the Research and Development Expenditure Credit (RDEC) scheme — into a single merged scheme. Understanding which rules apply to your claim is essential.
Under the merged scheme, companies claim an above-the-line tax credit of 20% on qualifying R&D expenditure. This credit is included in your taxable income but is then offset against your corporation tax liability. For loss-making companies, the credit can often be surrendered for a cash payment, subject to a PAYE/NIC cap.
A separate, more generous route exists for loss-making SMEs that qualify as R&D intensive: the Enhanced R&D Intensive Support (ERIS) scheme. To access ERIS, a company must be an SME (broadly, fewer than 500 employees and either a turnover under €100 million or a balance sheet under €86 million) and must spend at least 30% of its total relevant expenditure on qualifying R&D. The ERIS rate is 27%, providing a significantly higher cash benefit for eligible businesses.
If your accounting period started before 1 April 2024, the old SME and RDEC rules may still apply. A qualified R&D adviser or accountant can confirm the correct regime for your specific periods.
Who Qualifies for R&D Tax Credits?
To claim R&D tax credits, your company must:
- Be a UK limited company subject to corporation tax (sole traders and partnerships cannot claim directly, though they may be able to restructure to benefit).
- Have carried out qualifying R&D activity — work that sought to achieve a genuine scientific or technological advance by overcoming uncertainty that could not be resolved through standard professional knowledge.
- Have incurred qualifying expenditure during the claim period.
There is no minimum spend threshold, though in practice very small claims may not justify the cost of preparation. There is also no requirement that the project succeeded: HMRC recognises that innovation involves risk, and a failed project can still generate a valid claim provided the activity met the qualifying criteria at the time it was undertaken.
Sectors where claims are particularly common include software and technology, engineering and manufacturing, life sciences and pharmaceuticals, food and drink production, construction, and financial services. However, the scheme is sector-agnostic — if your work involved genuine technological problem-solving, it is worth exploring.
What Costs Can You Include in a Claim?
Getting the qualifying expenditure right is where many claims fall short. Including ineligible costs — or missing eligible ones — can both undermine the claim's value and trigger compliance reviews. The main qualifying cost categories under the merged scheme are:
Staff costs — Salaries, wages, and employer NICs for employees who are directly and actively engaged in the R&D activity. Time-apportioned figures are acceptable where staff split their time between R&D and other work. Directors' remuneration also qualifies where those individuals are genuinely involved in R&D.
Subcontractor and externally provided worker costs — Under the merged scheme, 65% of payments to unconnected subcontractors for qualifying R&D work can be included. Costs must relate to work performed in the UK, with limited exceptions for overseas activity where there is no UK equivalent.
Consumable items — Materials, components, and utilities (water, fuel, power) that are used or transformed in the R&D process. Items that are subsequently sold commercially do not qualify.
Software — Licence fees for software that is directly used in the qualifying R&D activity.
Good record-keeping is vital. HMRC expects companies to maintain contemporaneous evidence of what work was carried out, who was involved, and how costs were allocated. Building this documentation as the project progresses is far more reliable than reconstructing it months later at claim time.
How to Make an R&D Tax Credit Claim
R&D tax credits are claimed as part of your company's corporation tax return (CT600). You will need to submit an Additional Information Form (AIF) to HMRC before or alongside your return — a requirement introduced in August 2023 — detailing the qualifying projects and expenditure categories.
The process in outline:
- Identify qualifying projects — Review your activities against HMRC's definition of R&D. Focus on work where your team faced genuine technical uncertainty that required investigation, not just the application of existing knowledge.
- Gather and apportion costs — Collate staff timesheets, payroll data, supplier invoices, and software licence records. Apply appropriate apportionment ratios where staff worked across multiple projects.
- Prepare the technical narrative — The AIF requires a clear explanation of each qualifying project: the scientific or technological advance sought, the uncertainties encountered, and how your team worked to overcome them. This narrative is the cornerstone of your claim and should be written by someone with both technical knowledge of the project and an understanding of HMRC's criteria.
- Submit with your CT600 — The AIF must be filed digitally through HMRC's online service. Retain all supporting documentation for at least six years.
Many businesses work with specialist R&D tax advisers to maximise their claims, particularly for complex multi-project submissions. Fees are typically charged as a percentage of the tax benefit, though fixed-fee arrangements are also available. If you are considering using a claim packager, check that they are registered with HMRC's agent services and are members of a professional body.
A note on cash flow: R&D claims can take several months to process, particularly if HMRC raises a compliance check. If your business needs liquidity while a claim is pending, short-term working capital facilities can bridge the gap. Providers such as Credicorp offer UK businesses access to short-term loans without requiring a personal guarantee — a useful option for directors who want to protect their personal assets while managing a temporary cash-flow gap.
Common Mistakes to Avoid
- Claiming for commercially routine work — Improvements made through existing techniques, without genuine technical uncertainty, do not qualify. HMRC distinguishes between routine development and genuine R&D.
- Missing the two-year deadline — Claims must be made within two years of the end of the accounting period. Missed deadlines cannot be extended.
- Inadequate documentation — HMRC compliance checks have increased significantly in recent years. A well-documented claim with a robust technical narrative is far less likely to attract scrutiny.
- Overlooking PAYE/NIC caps — The payable credit available to loss-making companies under the merged scheme is capped at three times the company's total PAYE and NIC liability for the year, plus £20,000. For companies with small payrolls, this can limit the cash benefit.
- Using non-compliant advisers — HMRC has taken enforcement action against a number of R&D claim packagers who submitted inflated or fraudulent claims. Ensure any adviser you use is reputable and transparent about their methodology.
R&D tax credits reward businesses that take risks and push boundaries — and with the right approach, claiming them need not be complicated. If you have been investing in innovation and have not yet explored your eligibility, the start of a new financial year is an ideal moment to take stock.