How do I apply for HMRC advance assurance on my R&D claim?

Deciding which service to apply for

You can’t apply for both services covering the same accounting period, so this decision has to be made once, up front.

Full claim advance assurance is the only option if you want assurance on your whole claim rather than one specific point — but it’s genuinely restricted to first-time claimants: not just your company, but every company linked to it in a group. One earlier claim anywhere in the group rules it out entirely.

Targeted advance assurance is the only option for a repeat claimant, and is usually the better choice for a first-time claimant too where the technical position is otherwise solid and only one specific point is genuinely in doubt — because it doesn’t put the whole claim at risk of a single refusal.

Applying for targeted advance assurance

You can make up to two applications, each covering exactly one project and one of four defined areas: whether the project meets the definition of R&D for tax purposes, whether overseas expenditure qualifies for relief, whether contracted-out R&D relief applies where the work is done for another company (see Who claims R&D relief when work is contracted out to another company?), or whether the company qualifies for exemption from the PAYE and National Insurance contributions cap.

The application is a standalone online form. You fill it in in one sitting—you can’t save your progress and come back—and you can’t attach any supporting documents, so everything HMRC needs must be stated directly in the form. You’ll need the company registration number, the project’s start date, contact details for the named competent professional and a senior company officer, an overview of the project, the relevant accounting period dates, forecast expenditure and duration, and — for an overseas expenditure application specifically — the justification for the overseas element. The company officer, an authorised agent, or an R&D adviser can complete it, but an agent must have proper authorisation on file (form 64-8 or COMP1) before applying.

HMRC aims to process the application within 40 calendar days, provided the information given is complete and accurate. You can’t apply again for the same project and area if HMRC has already given assurance on it for that period, and you’re excluded from applying at all if the company, or a connected person, has entered a disclosable tax avoidance scheme, been categorised as a Corporate Serious Defaulter, or has an open corporation tax enquiry — check these before applying, not after a refusal.

Applying for full claim advance assurance

Eligibility is narrower: this is only available where the claim would genuinely be the company’s first R&D claim, no company linked to it in a group has claimed before, and the company meets the SME thresholds of turnover under £2 million and fewer than 50 employees.

The application itself works differently from targeted assurance. You apply online through a Government Gateway-authenticated digital form, or — if you can’t apply online — either fill the same form in and print it to post, or download and complete it in Adobe Reader before posting it. You, or your agent, can complete it. The information required is more substantial than targeted assurance’s: company accounts, your Companies House registration details, a named main contact with genuine knowledge of the R&D, and a detailed account of the scientific or technological uncertainties involved and how you tried to resolve them, alongside the relevant cost information. HMRC will typically follow up by arranging a short phone call with the named contact rather than deciding on the paperwork alone.

Where assurance is agreed, it covers the whole claim and applies across the company’s first three accounting periods, not only the one under review.

HMRC does not publish a turnaround target for full claim advance assurance, unlike the 40-day figure given for targeted assurance. Treat that as a reason to chase actively rather than wait — the predecessor service this replaces had no reliable track record of responding to applications at all, let alone within a defined period.

Either way, this isn’t the claim itself

An assurance letter — from either service — is not a substitute for actually making the claim. You still have to meet the claim notification deadline where it applies, prepare the additional information form, and file the Company Tax Return in the normal way. The assurance is also conditional, not permanent: if the R&D activities described in the application change materially before you claim, the protection goes with them — see advance-clearances for why that matters and what it means in practice.