Do I need to pre-notify HMRC of an R&D claim?

Yes — first-time claimants, or companies that haven't claimed in the last 3 years, must submit a Claim Notification Form within 6 months of the end of the relevant accounting period. Missing this deadline blocks the claim entirely.

What is the Additional Information Form?

Since August 2023, every R&D claim must be supported by an Additional Information Form (AIF) submitted before the CT600. It captures project descriptions, technological advances and uncertainties, qualifying costs, and details of the senior technical lead and agent.

Can subcontracted R&D be claimed?

Under the merged scheme, the company that **decides** the R&D and contracts it out can usually claim — not the subcontractor doing the work. This is a major change from the old SME scheme. Connected-party subcontracting uses actual cost rather than invoice value.

How long does an R&D claim take to process?

HMRC aims to process most claims within 40 working days but has been carrying out enhanced compliance checks since 2023. Allow 2–6 months and keep robust contemporaneous evidence to support the claim.

Guides

R&D Tax Relief for SMEs: The Merged Scheme Explained

From accounting periods beginning on or after 1 April 2024, most UK companies claim R&D tax relief under a single merged RDEC-style scheme. Loss-making R&D-intensive SMEs can use Enhanced R&D Intensive Support (ERIS) for a higher rate.

2 min read·Updated 30 April 2026

Quick answers

What is the R&D tax relief merged scheme?

From April 2024, most UK companies claim R&D tax relief through one merged scheme that works like the old RDEC. It gives an above-the-line credit of 20% of qualifying R&D spend, with a net Corporation Tax benefit of roughly 15% for companies on the 25% main rate.

What is ERIS and who qualifies?

Enhanced R&D Intensive Support (ERIS) is a higher-rate route for loss-making SMEs whose R&D spend is at least 30% of total expenditure. They get an 86% additional deduction plus a 14.5% payable credit on the surrendered loss — about 27p per £1 of R&D spend.

What costs qualify for R&D tax relief?

Qualifying costs include staff (salary, employer NI and pension), externally provided workers, subcontracted R&D, consumables, software, cloud computing and data licences. Most overseas R&D costs no longer qualify unless geographical, regulatory or legal reasons make UK-based work impractical.

What changed in April 2024?

For accounting periods starting on or after 1 April 2024, the old SME R&D scheme and the large-company RDEC merged into a single scheme. A separate route — Enhanced R&D Intensive Support (ERIS) — exists only for loss-making, R&D-intensive SMEs.

The merged scheme

Works like the old RDEC: an above-the-line credit of 20% of qualifying R&D expenditure
Credit is taxable, so the net benefit is roughly 15% for companies paying the 25% main rate of Corporation Tax
Available to companies of all sizes, including those receiving subsidies or doing subcontracted R&D

ERIS — for loss-making R&D-intensive SMEs

A company qualifies as R&D-intensive if at least 30% of its total expenditure is on R&D (reduced from 40% in April 2024). Qualifying SMEs can:

Claim an 86% additional deduction on qualifying R&D spend
Surrender the resulting loss for a 14.5% payable credit
Net benefit ≈ 27p per £1 of R&D spend

What counts as R&D?

Work qualifies if it seeks an advance in science or technology by resolving scientific or technological uncertainty that a competent professional in the field couldn't readily deduce. Routine product changes, market research and pure data analysis usually don't qualify.

Qualifying expenditure

Staff costs (salary, employer NI, employer pension)
Externally provided workers (EPWs) — restricted, see below
Subcontracted R&D — now claimable by the company that decides the R&D, not the subcontractor
Software, consumables, cloud computing and data licences (since April 2023)
Payments to clinical trial volunteers

Restrictions

Overseas costs — generally restricted to UK-based EPWs and subcontractors, with narrow exceptions (e.g. geographical, legal or regulatory necessity)
Connected-party subcontracting uses actual cost, not the invoiced amount

How to claim

Pre-notify HMRC within 6 months of the period end if the company is a first-time claimant or hasn't claimed in the last 3 years.
Submit an Additional Information Form (AIF) before the corporation tax return — required for every claim since August 2023.
Include the claim in the CT600 and CT600L supplementary pages.
Keep contemporaneous project records: technical narratives, time tracking, cost analysis.

Time limit

You have 2 years from the end of the accounting period to submit a claim.

General guidance, not tax advice. Speak to a qualified accountant for advice tailored to your situation. Figures relate to the 2025/26 UK tax year. Source: HMRC, gov.uk.