If your company has an accounting period ending 31 March 2026, and you've never claimed R&D tax relief before, or haven't made a claim in the last three years, you have until 30 September 2026 to submit your Advance Notification Form to HMRC. That's this month.
If you miss it, your claim for this period can't go ahead, no matter how strong the underlying R&D work is.
This is a heads-up for first-time claimants, newly incorporated companies, and anyone returning to R&D tax relief after a gap. If any of that sounds like you, it's worth five minutes now to check where you stand.
Who needs to submit an ANF?
You must submit an Advance Notification Form, also known as a claim notification form, if one of two things is true:
- your company has never made an R&D tax relief claim before, or
- you haven't made a valid R&D claim in the three years before your claim notification period ends
If you've been claiming R&D relief every year without a break, you're in the clear. But if you're claiming for the first time, or you've taken a few years off from claiming, the Advance Notification Form is a mandatory step before your claim can be accepted.
Submitting an ANF doesn’t obligate you to submit a claim, so it’s a good idea to send off your ANF even if you’re not certain you’ll be claiming.
What is the deadline to submit an ANF?
Your claim notification period runs from the first day of your period of account to six months after it ends. For most companies, the accounting period and period of account are the same 12-month window, so this works out to six months after your year end.
For companies with an accounting period running from 1 April 2025 to 31 March 2026, the deadline comes at the end of this month. The claim notification window opened on 1 April 2025 and closes on 30 September 2026. If this is the company's first R&D claim, or its first in three years, it needs to get the ANF in before that date.
The claim itself might not be due for months, but the notification deadline arrives well before the tax return does, and it's easy to lose track of when the two aren't the same date. For more information about the deadline to submit your claim, check out our guide: What’s the Deadline to Make an R&D Tax Claim?
The exception to the three-year rule
There's a specific carve-out that catches some claimants off guard. A previous R&D claim doesn't count towards your three years if it relates to an accounting period beginning before 1 April 2023, and it was submitted through an amended Corporation Tax return that HMRC received on or after 1 April 2023.
In practice, that means a company that believes it claimed within the last three years, because it amended an old return recently, might still need to submit an ANF. If your last claim involved an amended return for an older period, it's worth checking this properly rather than assuming you're exempt.
What do you need to submit?
The ANF itself is straightforward, and HMRC isn't asking for detailed evidence at this stage. You'll need:
- Your company's Unique Taxpayer Reference (UTR), matching the one on your Company Tax Return
- The name, role, and contact details of the senior internal R&D contact, usually a director
- Contact details for any agents or advisers involved in the claim
- Your accounting period and period of account dates
- The number of R&D projects in the period
- A high-level description of your planned R&D activities
One practical point: you can't go back into the form once you've submitted it, so save a copy before you do.
Not sure if you're affected?
The quickest way to find out is using a free Advance Notification Form Checker. It confirms whether you're in scope and gives you your exact deadline in a few steps.
Missing this deadline is avoidable, and it's usually down to timing rather than eligibility. If you'd like help working out whether the ANF applies to your company, or want support getting your R&D claim moving, get in touch and we'll walk you through it.
