R&D Tax Credits or a Grant First? A Decision Framework for UK Deep-Tech Companies

If your company is spending real money on research and development, the question isn't whether to use the UK's R&D tax credit system, it's whether to claim it now, wait and pair it with a grant, or sequence the two deliberately. Since April 2024, HMRC's rules mean you can often do both on the same project, but the order you approach them in still changes how much you end up with and how much time you spend getting it.

Two different mechanisms, easily confused

R&D tax credits and Innovate UK grants both exist to support R&D spending, but they work on opposite logic.

R&D tax relief is a retrospective, non-competitive claim against costs you have already incurred. You file it through your Corporation Tax return, HMRC assesses whether your activity and costs qualify against its own technical criteria, and you either get money back, a reduced tax bill, or (if loss-making) a payable credit. Nobody scores your project against anyone else's. If the spend qualifies, it qualifies, whether you're the only company that claimed that year or one of thousands.

A grant is prospective and competitive. You apply before you spend the money, describe a project that hasn't happened yet, and are assessed against every other applicant in that round for a fixed pot. Most Innovate UK competitions fund a minority of applicants, so a grant is never guaranteed the way a qualifying tax claim effectively is.

Retrospective relief vs prospective funding

That timing difference is the whole strategic point. Tax relief rewards R&D you were always going to do anyway, once a year, with modest effort relative to the return. A grant asks you to describe a specific, often more ambitious project in advance and compete for it, which takes weeks of proposal-writing time with no guarantee of an award at the end.

As of September 2026, the current UK regime (in force for accounting periods beginning on or after 1 April 2024) merged the old SME and RDEC schemes into a single R&D Expenditure Credit. It pays a taxable credit worth 20% of qualifying R&D expenditure, which nets out to roughly 15% to 16.2% after Corporation Tax depending on whether you pay the main or small profits rate. Loss-making companies where qualifying R&D spend is at least 30% of total expenditure can instead claim under Enhanced R&D Intensive Support (ERIS), worth up to 27%, a rate that HMRC dropped the qualifying threshold to from 1 April 2025 (previously 40%). Both figures are current guidance as at this writing; always check gov.uk before you rely on a specific percentage, since rates and thresholds have moved twice in three years.

Can you claim both on the same project?

Often, yes, and this is the part that has genuinely changed. Under the old SME scheme, receiving a grant against a project reduced the R&D tax relief available on it, because grant-funded costs were treated as "subsidised expenditure" and pushed into the far less generous RDEC rate. HMRC's own technical note on the merged scheme confirms that restriction was not carried forward: where a company receives a grant covering part of its R&D costs, the amount of relief available under the merged scheme is no longer reduced as a result.

In practice, that means an Innovate UK grant and a full-value R&D tax credit claim can now sit on the same project, for accounting periods starting on or after 1 April 2024. This is a material change from the position that shaped a lot of the "don't let a grant wreck your tax claim" advice still circulating online, some of which predates the merger and is now out of date. If you're relying on guidance written before 2024, treat it as historical rather than current.

That said, the detail still depends on your company's specific facts, your accounting period start date, and exactly how the grant is structured, so this is genuinely a point to confirm with an accountant who specialises in R&D claims before you file, not something to assume holds for every grant and every company.

A practical sequencing framework

For a deep-tech company deciding where to put its limited grant-and-tax-relief attention this year, a useful order is:

1. Claim the tax relief you're already entitled to, every year, without exception. It requires no competition, no waiting for a deadline, and no risk of rejection if the activity genuinely qualifies. Treat it as background process, not a strategic decision.
2. Check grant fit before you invest in a proposal. A grant application typically takes far more person-hours than a tax claim, for a lower probability of success. Before committing that time, work out honestly whether your project matches what the specific competition is actually looking to fund, its technology readiness level expectations, and its sector scope, rather than assuming eligibility from the headline description.
3. If you win the grant, factor the merged scheme into your tax planning for that accounting period, rather than assuming the old subsidised-expenditure discount still applies. Loop your accountant in early so the claim is structured correctly from the start.
4. Don't let grant-chasing crowd out the tax claim, or vice versa. They draw on different internal resources (finance and compliance for one, technical proposal-writing for the other), so running both in parallel is usually realistic for a well-organised R&D team, not an either/or choice.

When to prioritise one over the other

Tax relief should never be an "instead of" decision, since it's near-automatic once you're spending qualifying costs. The real choice is how much effort to put into chasing a grant on top of it.

Lean toward pursuing a grant when your project is more ambitious than what you'd self-fund anyway, when non-dilutive cash before spend (rather than relief after) actually changes what you can attempt, or when the credibility of a UKRI or sector-body award matters to future investors or customers. Lean away from it when your project doesn't clearly match a live competition's scope, when the proposal effort would come at the cost of actually doing the R&D, or when your realistic odds in that specific round are low. Knowing when not to apply is as much a part of a sound funding strategy as knowing when to.

How GrantHero helps once you've decided a grant is worth pursuing

Tax relief is a compliance decision your accountant should own. Deciding whether a specific grant round is worth your team's time, and then building a competitive application if it is, is a different job, and it's the one GrantHero exists for. Our free Discovery plan lets you check whether live competitions genuinely match your company's technology and stage before you commit any proposal-writing time, the same honest filtering we'd apply to the sequencing question above. If a competition is a real fit, paid plans on our pricing page add AI-assisted drafting and expert review from people experienced in assessing these applications, on a per-application basis rather than a subscription you pay whether or not you're applying that quarter. We won't tell you a grant is worth applying for if it isn't; see our take on whether Innovate UK funding fits your business for the same reasoning applied to the UK's largest innovation funder.