What Is the HMRC R&D Additional Information Form?
You’ve probably heard about HMRC’s new Additional Information Form (AIF) for R&D tax claims, but if you're like most people, you're still not 100% sure what it is, whether it applies to you, or how serious it is if you get it wrong.
And you're right to be cautious. Mistakes could mean your entire R&D claim is rejected.
The AIF is now a mandatory step for all companies submitting an R&D tax relief claim in the UK. It’s HMRC’s way of tightening standards and reducing fraud. If you're claiming R&D relief, you must send this form before submitting your revised CT600. If you miss this step, your claim won’t be considered.
Why It Matters
Although introduced in August 2023, many qualifying companies still aren't submitting the AIF. Recently, a software development company spent over £1 million developing their product but missed the AIF submission due to poor advice, losing between £175,300 and £269,700 in tax savings.
Who Needs to Submit the R&D Additional Information Form?
All companies claiming R&D tax relief for accounting periods starting on or after 1 April 2023 must submit an AIF.
- You must submit one AIF per accounting period.
- For periods over 12 months, submit two separate AIFs.
- The AIF must precede the CT600 submission.
Consequences of Not Submitting the Form
If you don’t submit an AIF:
- Your R&D claim will be rejected outright.
- HMRC will remove R&D relief from your company tax return.
- Missing deadlines (2 years from the year-end) means losing potential relief permanently.
Can Accountants Complete the AIF on Behalf of Clients?
Yes, but accuracy is crucial. Mistakes can lead to claim rejection, and the client remains legally responsible for the submission's accuracy.
Information Needed Before Starting the Form
Gather these essentials first:
Company Information
- Name, contact details, UTR, accounting period dates
- Employer PAYE reference number, VAT registration number
- Business type (SIC code), connected companies (for enhanced support)
Contact Details
- Main internal senior R&D contact
- All involved agents
Project Summaries
- Detailed descriptions of R&D projects claimed
Claim Type and Cost Breakdown
- R&D scheme type: SME, RDEC, or merged
- Cost categories: staff, software, subcontractors, indirect activities
Narrative Evidence
- Baselines, advances, uncertainties, and resolution attempts
How Long Does the Form Take to Complete?
- Well-prepared: approximately 2 hours.
- Poorly prepared: 6 hours or more, risking claim rejection.
Step-by-Step Guide to Completing the AIF
Step 1: Access the Form
Log into your HMRC agent services account.
Step 2: Enter Company and Agent Details
Ensure the UTR, accounting dates, and contact details align with CT600.
Step 3: Breakdown Qualifying Costs
Enter totals for:
- Staff
- Externally provided workers
- Software
- Consumables
- Subcontracted R&D
- Clinical trial volunteers (if applicable)
Step 4: Include Project Details
Provide clear descriptions covering:
- Baseline science or technology
- Advancements attempted
- Uncertainties encountered
- How uncertainties were addressed
Step 5: Confirm R&D Intensive Scheme Eligibility
If applicable, confirm eligibility.
Step 6: Declarations and Submission
Tick boxes to confirm accuracy and submit.
Common Mistakes on the AIF
- Submitting CT600 before AIF
- Vague or marketing language in project narratives
- Including non-qualifying activities
- Poor record-keeping resulting in missing costs
How Detailed Should Technical Descriptions Be?
Descriptions should clearly and concisely outline:
- Baseline
- Advances
- Uncertainties
- Resolution attempts
Avoid jargon, waffle, and commercial justifications.
How Many Projects Should You Include?
- 1 to 3 projects: Include all
- 4 to 10 projects: Include at least 3 covering 50% of costs
- Over 10 projects: Include at least 3 covering 50% of costs, or the top 10 highest-cost projects
Does the AIF Increase HMRC Enquiry Risk?
Unclear or generic responses increase enquiry risk. HMRC identifies red flags such as:
- Copy-paste narratives
- Excessive costs for the business size
- Descriptions resembling routine work
Supporting Evidence Submission
AIF itself doesn't accept attachments. Additional evidence like timesheets, emails, or technical documentation should accompany your CT600 submission.
Reusing Previous R&D Information
Avoid direct copy-pasting. Each year's uncertainties and resolutions differ, so provide accurate, fresh narratives annually.
Do You Still Need to Submit a CT600 Separately?
Yes. The AIF supplements but does not replace the CT600 or the tax computation. Ensure alignment of R&D numbers across all documents to avoid enquiries.
Penalties for Incorrect or Incomplete Submissions
Penalties range from 0% to 100%, depending on:
- Behaviour (careless, deliberate, concealed)
- Disclosure type (prompted, unprompted)
| Behaviour | Unprompted Disclosure | Prompted Disclosure |
|---|---|---|
| Careless | 0% - 30% | 15% - 30% |
| Deliberate (not concealed) | 20% - 70% | 35% - 70% |
| Deliberate (concealed) | 30% - 100% | 50% - 100% |
Real Example
A client previously made an incorrect claim leading to an HMRC enquiry. Although penalties initially totaled £15,000, proactive steps to correct the claim eliminated the penalty.
When to Get Specialist Help
Seek expert help if you:
- Don’t clearly understand R&D criteria
- Struggle with technical descriptions
- Have difficulties calculating costs
Costs of Using an R&D Expert
Fees vary by success percentage, fixed fees, or hourly rates. Many specialists charge a percentage of tax saved or fixed fees. More details are available here.
Tracking and Monitoring Your Submission
After submission:
- Obtain receipts for AIF and CT600
- Monitor updates through your HMRC account
- Typically updated within 25 days
Final Submission Checklist
Ensure:
- Accurate narratives for required projects
- Cost figures match your CT600
- Reviewed for typos and clarity
- Submitted AIF before the CT600
Ready to Submit with Confidence?
We’ve helped companies across various sectors successfully submit AIFs without rejections.
If you're unsure where to start or prefer expert support, book a call. We’ll guide you through the process and help you submit an accurate, robust AIF.