Tax incentive guide: 2026/27
UK R&D Tax Credit 2026/27: Merged Scheme, RDEC 20%, R&D-Intensive 27%
The merged R&D scheme that took effect on 1 April 2024 combining the previous SME and RDEC schemes into a single 20% above-the-line credit (16.2% net of CT), the enhanced 27% rate for R&D-intensive loss-making SMEs (30%+ R&D spend share since April 2025), the qualifying activity test under BIS guidelines, the mandatory Additional Information Form requirement, and the tightened software development criteria that have raised the bar materially for SaaS and ML claimants.
Overview - the merged scheme
The UK R&D tax credit scheme was substantially restructured from 1 April 2024 under Finance (No. 2) Act 2023 schedule 1, combining the previous SME and Research and Development Expenditure Credit (RDEC) schemes into a single "merged scheme" based on the RDEC mechanism. The merged scheme delivers a 20% above-the-line credit on qualifying R&D expenditure, taxed at the company main Corporation Tax rate - giving an effective net benefit of around 16.2% for small-profits-rate companies (20% × (1 - 19%)) and 15.0% for main-rate companies (20% × (1 - 25%)). A separate enhanced rate of 27% net applies to loss-making SMEs that meet the R&D-intensive test (R&D spend = 30% or more of total qualifying expenditure, threshold reduced from 40% to 30% on 1 April 2025).
The 2024 reform represents the most significant restructuring of UK R&D incentives since they were introduced in 2000. The reform had three drivers. First, fiscal cost: the pre-2024 SME scheme had become substantially more expensive than originally estimated, with HMRC published statistics showing around £3.1 billion of SME scheme relief in 2021-22 against an original forecast around £1.0bn. Second, fraud and error: a 2023 HMRC investigation estimated around £1.13 billion (16.7%) of SME scheme claims were fraudulent or in error, prompting the merged scheme as a structural simplification. Third, alignment with international norms: the merged 20% above-the-line rate aligns with comparable French Crédit d'Impôt Recherche and US Research Tax Credit mechanisms.
The practical impact on most claimant companies is a meaningful reduction in headline benefit. Pre-2024 profitable SMEs received around 21.5% net benefit on qualifying R&D; post-2024 the same companies receive around 16.2% net. Loss-making SMEs saw the largest reduction: from 33.35% cash credit pre-April-2023 to 10% from April 2023 onwards under the pre-merged-scheme cap-down, then 16.2% under the merged scheme - except for R&D-intensive loss-makers who get 27% net under the enhanced rate. The enhanced 27% rate for R&D-intensive SMEs (30%+ R&D spend share) is now the most generous element of the post-2024 regime and is specifically designed to support genuine startup R&D where the company has not yet built revenue but is concentrating substantial spend on R&D.
Pre-2024 vs post-2024 scheme comparison
| Company type | Pre-1 April 2024 | Post-1 April 2024 | Notes |
|---|---|---|---|
| Profitable SME | Enhanced expenditure deduction at 186% (raised from 230% before April 2023) | Merged scheme: 20% RDEC-equivalent credit (16.2% net of CT) | Profitable SMEs saw the most dramatic change - the pre-2024 enhancement gave around 21.5% net benefit; the post-2024 16.2% is a material reduction. |
| Loss-making SME (R&D-intensive) | Surrender of losses for 14.5% cash credit (until April 2023), then 10% (until April 2024) | Enhanced R&D-intensive rate at 27% net for SMEs with 30%+ R&D spend share | R&D-intensive threshold dropped from 40% to 30% on 1 April 2025. Provides the most generous treatment for genuinely R&D-focused startups. |
| Loss-making SME (non-R&D-intensive) | Surrender of losses for 10% cash credit (post-April 2023) | Merged scheme: 20% RDEC-equivalent credit (around 16.2% net of CT, with cash payment subject to PAYE cap) | Non-R&D-intensive loss-making SMEs now receive the same headline rate as profitable companies, ending the pre-2024 dual-track system. |
| Large company (formerly RDEC scheme) | Above-the-line RDEC at 20% (raised from 13% on 1 April 2023) | Same 20% above-the-line credit under merged scheme (no change) | The merged scheme is structurally based on the RDEC mechanism; large companies see no material change in rate. |
| Foreign-resident company with UK PE | Eligible for RDEC at 20% (post-April 2023) | Eligible for merged scheme at 20% via the UK permanent establishment | Non-UK head office companies with R&D performed in the UK by a UK permanent establishment can claim under the merged scheme. |
Worked example - R&D-intensive SME claim
A loss-making technology startup with total qualifying expenditure of £800,000 and R&D expenditure of £500,000 (£300,000 other operating costs):
| Component | Value | Notes |
|---|---|---|
| Qualifying R&D expenditure | £500,000 | Staffing 70% (£350k), EPW 20% (£100k) at 65% allowed, software/cloud 10% (£50k). |
| Total qualifying expenditure | £800,000 | R&D plus all other qualifying costs. |
| R&D share | 62.5% | Above the 30% R&D-intensive threshold from 1 April 2025. |
| Applied rate | 27.0% net | R&D-intensive enhanced rate. |
| Cash claim from HMRC | £135,000 | Subject to PAYE/NIC cap (greater of £20,000 or 3× UK PAYE+NIC liability). |
The same loss-making SME under the pre-merged scheme (April 2023 to March 2024) would have received around £50,000 (10% rate on the £500,000 R&D). The R&D-intensive enhanced rate provides a meaningful uplift for genuinely R&D-focused startups. The PAYE/NIC cap is the binding constraint for many early-stage startups with low UK employment - a startup with 5 UK employees and £200,000 of PAYE+NIC has a cap of £600,000 (3×) which comfortably covers this £135,000 claim. A startup with all-overseas employees and £20,000 of UK PAYE+NIC would have a £60,000 cap (3× £20k) limiting claim size to £60,000 regardless of R&D spend.
Qualifying R&D activity - the two-limb test
HMRC applies the BIS Guidelines (Department for Business, Innovation and Skills "Guidelines on the Meaning of Research and Development for Tax Purposes") which define qualifying R&D as work that seeks an "advance in science or technology" through the "resolution of scientific or technological uncertainty". The test has two limbs and both must be satisfied:
- Advance in science or technology. The activity must seek to extend overall knowledge or capability in a field of science or technology beyond what is publicly available. The advance is field-wide, not company-wide - solving a problem that other competent professionals have already solved (even if not within your company) does not count as an advance. A useful test: would publication of the R&D output in a peer-reviewed journal or technical conference be considered novel by the relevant technical community? If yes, advance likely. If no (because the answer is in published textbooks or routine professional knowledge), no advance.
- Resolution of uncertainty. The advance must require resolution of scientific or technological uncertainty - that is, the answer or method to achieve the advance must not be readily deducible by a competent professional in the field. Pure routine development applying known methods is not R&D regardless of how complex or labour-intensive the work is. The "competent professional" test is applied strictly: would a competent professional reading the problem statement be able to solve it using known techniques? If yes, no R&D. If no (genuine uncertainty about which approach will work), R&D qualifies.
Typical qualifying activity: novel materials development (new polymer formulations, advanced ceramics, biotechnological scaffolds); biotech assay development for novel biomarkers; software engineering on genuinely new architectures (e.g. novel distributed ledger consensus mechanisms, novel ML training methods with methodological advance); unique manufacturing processes (e.g. precision additive manufacturing tolerances beyond commercial state of art); custom hardware design with non-obvious engineering integration; novel data structures or algorithms (e.g. new approximate computing techniques).
Typically non-qualifying: routine product development using known materials and processes; market research and consumer testing; aesthetic and visual design; software development using standard frameworks (React, Django, Rails, .NET, Vue, Angular) and libraries; training ML models on private data using off-the-shelf tools (PyTorch, TensorFlow, scikit-learn) without methodological advance; applying off-the-shelf APIs to business problems; building white-label SaaS products from existing components; user-interface and user-experience design; system integration using standard middleware; bug fixing and routine maintenance.
Compliance - AIF, pre-notification, documentation
HMRC has materially tightened R&D compliance since 2023. Three procedural requirements now apply:
- Pre-notification of intent to claim (CTA 2009 s1142A) - for companies that have not claimed R&D in the prior 3 accounting periods, pre-notification of intent to claim must be submitted to HMRC within 6 months of the start of the relevant accounting period. Missing the pre-notification window invalidates the claim entirely for that period. For a 1 April 2026 to 31 March 2027 accounting period the pre-notification deadline is 30 September 2026.
- Additional Information Form (AIF) - mandatory for all claims submitted on or after 8 August 2023. Submitted online via the HMRC R&D portal before or with the CT600 return. Requires at least three project descriptions covering 50% of the claim amount, with technical advance, uncertainty resolved, and qualifying expenditure for each. Submissions without AIF are automatically rejected.
- Contemporaneous technical documentation - HMRC enforces documentation requirements robustly under the Mandatory Random Enquiry Programme. Documentation should include project descriptions with the technical advance and uncertainty articulated, personnel records linking employee hours to specific R&D projects, technical decision records showing the resolution of uncertainty during the period, and clear separation between qualifying R&D activity and routine development. Retrospective reconstruction of qualifying activity is heavily disadvantaged in MREP review.
Around 30% of submitted claims are picked up by MREP for detailed examination, even where the underlying claim is genuine. HMRC R&D-claim rejection rates rose from around 5% in 2020 to around 18% in 2023/24 per HMRC published statistics. Specialist R&D tax advice is now strongly recommended for any claim above £30,000 to reduce the risk of rejection or extended enquiry. Engaging a HMRC-recognised R&D adviser (ICAEW, ACCA, CIOT, or specialist R&D firm with HMRC track record) is generally cost-effective vs the risk of claim rejection.
Frequently asked questions
What is the UK R&D tax credit and who can claim?
The UK R&D tax credit is the principal Government incentive for business investment in research and development, delivered through the Corporation Tax system. A UK Limited company that undertakes qualifying R&D activity can claim either an enhanced tax deduction (reducing taxable profit and the resulting CT bill) or, where the company is loss-making, surrender the relevant loss for a cash payment from HMRC. The scheme was substantially restructured from 1 April 2024 into a "merged scheme" combining the previous SME and RDEC schemes into a single above-the-line 20% Research and Development Expenditure Credit (RDEC) - delivering an effective 16.2% net benefit (20% × (1 - 19% CT rate)). A separate enhanced R&D-intensive SME rate of 27% net applies to loss-making SMEs where R&D spend is at least 30% of total qualifying expenditure. Sole traders and partnerships are not eligible - only UK Limited companies subject to UK Corporation Tax can claim.
What counts as qualifying R&D activity?
HMRC applies the BIS guidelines (Department for Business, Innovation and Skills "Guidelines on the Meaning of Research and Development for Tax Purposes") which defines R&D as work that seeks an "advance in science or technology" through the "resolution of scientific or technological uncertainty". Two limb test: (1) the activity must seek to extend knowledge or capability in a field of science or technology beyond what is publicly available; (2) the activity must resolve uncertainty that could not be straightforwardly resolved by a competent professional in the field. Routine product development, market research, aesthetic design, software customisation using existing tools, and replication of competitor products do NOT qualify. Examples that typically qualify: novel materials development, biotech assay development, software engineering on novel architectures or algorithms (e.g. distributed ledger consensus, novel ML training methods), unique manufacturing processes, custom hardware design with non-obvious engineering. HMRC has tightened software qualification significantly since 2023 - "applying off-the-shelf machine learning to a business problem" is generally not qualifying unless there is genuine technical advance in the methodology.
How is the merged scheme rate calculated?
The merged scheme delivers a 20% Research and Development Expenditure Credit (RDEC) on qualifying R&D expenditure, taxed at the company main Corporation Tax rate (19% for profits below £50,000, 25% above £250,000 with marginal relief between). For a profitable company on the main rate the net benefit is approximately 20% × (1 - 25%) = 15.0%; for a small profits company at 19% the net is approximately 20% × (1 - 19%) = 16.2%. For loss-making companies the credit can be received as cash from HMRC, subject to the PAYE / NIC cap (the cash payment is capped at the greater of £20,000 or 3x the claimant company UK PAYE and NIC liability for the period). The PAYE cap was introduced to deter fraudulent R&D claims from companies with no genuine UK employment substance.
What is the R&D-intensive SME enhanced rate?
A separate enhanced rate of 27% (net cash equivalent) applies to loss-making SMEs where qualifying R&D expenditure is at least 30% of total qualifying expenditure. The threshold was originally 40% when announced in November 2023; reduced to 30% from 1 April 2025 to expand the eligible cohort. The enhanced rate operates by allowing the company to surrender the enhanced expenditure for a cash credit at the higher rate. For a loss-making R&D-intensive SME with £500,000 of qualifying R&D expenditure, the enhanced rate delivers a cash claim of around £135,000 vs around £81,000 under the standard merged scheme. SME definition: under 500 employees AND turnover under €100m OR balance sheet under €86m (the standard EU SME thresholds adopted into UK R&D legislation). The enhanced rate is the most generous element of the post-2024 regime and is specifically designed to support genuine startup R&D.
How do I submit a claim?
Three-step process. (1) Maintain contemporaneous records of qualifying R&D activity throughout the accounting period - project descriptions, technical advance sought, uncertainty resolved, personnel hours, subcontractor costs, software and equipment used. HMRC will challenge claims with weak documentation. (2) Submit an Additional Information Form (AIF) before or with the company tax return - this is mandatory from 8 August 2023 and provides HMRC with project descriptions, claim amount, and the senior R&D contact. Claims without AIF are automatically rejected. (3) Include the R&D claim on the company CT600 corporation tax return for the relevant accounting period. Claim must be made within 2 years of the end of the relevant accounting period; pre-notification of intent to claim is now mandatory for any company that has not claimed R&D in the prior 3 years (the pre-notification window is 6 months from the start of the relevant accounting period). Missing the pre-notification window invalidates the claim for that year.
What is the Additional Information Form (AIF) requirement?
The AIF has been mandatory for all R&D claims submitted on or after 8 August 2023 under CTA 2009 section 1142A. The AIF must be submitted online via the HMRC R&D portal before or at the same time as the CT600 return; submission of a CT600 with an R&D claim but no AIF triggers automatic rejection of the R&D element. The AIF requires: company UTR and registered office, accounting period dates, claim amount and rate (merged scheme RDEC, R&D-intensive SME enhanced, or transitional pre-2024 SME), at least three project descriptions covering 50% of the claim (with technical advance sought, uncertainty resolved, and qualifying expenditure for each), senior R&D contact details, and the name of any agent who advised on the claim. The AIF is the single biggest compliance-burden increase introduced with the merged scheme - many small R&D claims are no longer cost-effective to make because of the documentation burden vs the relatively small cash benefit.
What expenditure qualifies under the merged scheme?
Six main categories of qualifying expenditure. (1) Staffing costs - salaries, employer NI, pension contributions for directly-employed R&D staff (typically 60% to 80% of a claim). (2) Externally provided workers (EPWs) - workers engaged through staffing agencies or umbrella companies who work alongside the claimant company R&D team. Under the merged scheme, 65% of EPW cost is allowed (down from 100% under the pre-2024 SME scheme). (3) Subcontracted R&D - costs of contracting R&D work to a third party. Under the merged scheme rules from 1 April 2024, only the claimant company contracts can be claimed for subcontracted R&D - the previous SME-scheme rule that allowed the contractor (the third party) to claim on the same work was removed. (4) Software, data and cloud-computing costs - directly used in R&D, including SaaS subscriptions for R&D platforms. (5) Consumables - materials transformed or consumed in R&D activity. (6) Prototype and clinical trial costs (limited categories). Capital equipment, raw materials sold in finished products, and overheads are NOT directly qualifying (but may be partially in scope under enhanced rules).
How long does HMRC take to process an R&D claim?
Pre-2023 HMRC routinely processed R&D claims within 28 days. From 2023 onwards HMRC has materially tightened compliance, with processing times typically 60 to 120 days for straightforward claims and 6 to 12 months for claims that enter the Mandatory Random Enquiry Programme (MREP) or are flagged for compliance review. Around 30% of submitted claims are picked up by MREP for detailed examination, even where the underlying claim is genuine. Claims that pass MREP examination ultimately receive the relief but with a substantial delay. Claims that fail examination either receive reduced relief or full rejection. HMRC R&D-claim rejection rates rose from around 5% in 2020 to around 18% in 2023/24 per HMRC published statistics. Specialist R&D tax advice is now strongly recommended for any claim above £30,000 to reduce the risk of rejection or extended enquiry.
Can software development claims still succeed?
Yes - but the threshold has materially tightened. HMRC published Software Development Guidelines in February 2024 setting out the test for qualifying software R&D. Qualifying examples: novel algorithms or data structures (not just novel applications of known algorithms), novel architecture solutions (e.g. genuinely-new distributed systems consensus mechanisms), advances in ML methodology (not just fine-tuning known models on private data), and qualifying work on integration of incompatible systems where the integration challenge requires genuine technical advance. Non-qualifying examples: building applications using standard frameworks and libraries (React, Django, Rails, .NET), training ML models on private data using off-the-shelf tools (PyTorch, TensorFlow, scikit-learn) without methodological advance, applying off-the-shelf APIs to business problems, building white-label SaaS products from existing components, and creating user interfaces or visual designs. The "competent professional" test is applied strictly: would a competent software engineer reading the problem statement be able to solve it using known techniques? If yes, no R&D. If no (genuine uncertainty about which approach will work), R&D qualifies.
What are the penalties for incorrect R&D claims?
HMRC operates the standard CTA 2009 penalty regime for incorrect R&D claims, with rates depending on whether the error is careless, deliberate, or deliberate and concealed. Careless errors (most common - poor documentation or weak qualifying activity) attract 0-30% of the overclaimed amount. Deliberate errors (knowingly claiming for ineligible activity) attract 35-70%. Deliberate and concealed errors (active misrepresentation of qualifying activity) attract 50-100% plus possible criminal sanctions. The 2023-2024 HMRC R&D enforcement focus has been on a cohort of "rogue R&D advisor" firms that submitted speculative claims on behalf of small businesses - HMRC has rejected many of these claims and pursued penalties against both the claimant companies and the agent firms. Use only HMRC-recognised R&D advisors and ensure contemporaneous documentation of the qualifying R&D activity. The CIRD83000 manual sets out the compliance approach in detail.
Can I claim for past R&D?
Yes - the standard claim window is 2 years from the end of the relevant accounting period. A company whose accounting period ended 31 December 2024 can claim until 31 December 2026 for R&D undertaken in calendar 2024. Earlier years are out of time except in narrow exception cases (HMRC error, recent grant of permission). Companies that have never previously claimed R&D should also note the new pre-notification requirement under CTA 2009 section 1142A: pre-notification of intent to claim must be made within 6 months of the start of the relevant accounting period for first-time claimants (and for companies that have not claimed in the prior 3 years). Missing the pre-notification window invalidates the claim. For first-time claimants in 2026/27 the pre-notification deadline is 6 months after the start of the accounting period - i.e. by 30 September 2026 for a 1 April 2026 to 31 March 2027 period. This is a tighter window than many small businesses realise.
How does R&D tax credit interact with grants and subsidies?
R&D expenditure funded by certain notified state aid grants (Innovate UK grants, Horizon Europe funding, EU R&D grants) cannot also qualify for the merged scheme R&D credit - the two are mutually exclusive on the same expenditure. The taxpayer must choose which relief mechanism to claim against the specific R&D spend. For SMEs the grant route is typically more cash-favourable (Innovate UK grants typically fund 50% to 70% of project cost upfront vs the 16.2% net merged scheme credit), but the grant route has more competitive application processes and project-completion reporting requirements. Non-state-aid grants (private foundation funding, commercial customer-funded R&D) do not preclude the R&D credit - the customer-funded R&D rules under the merged scheme allow claims subject to a 65% restriction (similar to the EPW restriction). Specialist advice essential when grant funding and R&D credit are being considered jointly.
Related calculators and guides
- Corporation tax calculator - CT computation with marginal relief, used as the base for the R&D credit interaction.
- Capital allowances calculator - AIA, FYA and writing-down allowance on R&D-adjacent capital equipment.
- UK Corporation Tax rates guide - main rate, small profits rate and marginal relief.
- Sole trader vs Limited Company guide - structural choice (only Limited companies can claim R&D credit).
- Director loan account guide - common cash-flow vehicle for R&D-intensive startups.
- Autumn Budget 2024 summary - includes the R&D-intensive threshold drop from 40% to 30%.
- Family Investment Companies (FIC) guide - parallel structuring for high-net-worth founder wealth post-R&D-exit.