If you claimed R&D tax credits and included costs for subcontracted developers, you are in a higher risk category for an HMRC enquiry. HMRC sees subcontractor costs as one of the most common areas of error and abuse in R&D claims. That does not mean your claim is wrong. It means your evidence needs to be solid.
This article explains exactly what HMRC looks for in an R&D enquiry focused on subcontracted developers. It covers the documents you need, the questions they will ask, and how to organise your response before the letter arrives.
Why Subcontracted Developer Costs Trigger HMRC R&D Enquiries
HMRC receives thousands of R&D claims every year. A significant proportion include costs for external developers, contractors, or agencies. The problem for HMRC is distinguishing between genuine R&D subcontractor costs and routine software development that does not qualify.
Three things make subcontractor costs a red flag:
- Misclassification of qualifying activities. HMRC finds that many companies claim for bug fixes, routine maintenance, or standard feature additions that do not meet the R&D definition under the guidelines.
- Lack of direct control. If a subcontractor works independently with minimal direction from your company, HMRC may argue the work is not part of your R&D project. The rules require the company to own the intellectual property and direct the work.
- Inflated or duplicated costs. HMRC checks whether the same costs appear in both your R&D claim and your subcontractor's claim. This is a common compliance issue.
As ICAEW qualified accountants, we see these patterns regularly. A well-prepared file reduces the chance of a full enquiry and improves your position if one opens.
What HMRC Will Ask About Subcontracted Developers
An HMRC R&D enquiry letter typically arrives as a formal notice under Schedule 18 FA 1998. It will request specific information. For subcontracted developer costs, expect these questions:
Who Were The Subcontractors And What Did They Do?
HMRC will want names, company details, and a description of each subcontractor's role. They will compare this against your technical narrative to see if the work described matches the subcontractor's actual activities.
How Were The Costs Calculated?
They will ask for invoices, payment records, and the methodology used to identify qualifying costs. If you used a percentage allocation, they will want to see the basis for that percentage. A flat 50% allocation without supporting analysis will not hold up.
Was The Subcontractor Connected To Your Company?
Connected parties change the rules. If the subcontractor is a connected company (same director, family member, or shared ownership), HMRC applies different cost limits. For connected subcontractors, only 65% of the qualifying cost is eligible, and you must have a written contract in place before the work started.
Did The Subcontractor Claim R&D Relief On The Same Costs?
HMRC cross-checks claims. If your subcontractor also submitted an R&D claim that includes the same staff costs you are claiming, both claims will be reviewed. Double claiming is not allowed.
Documents You Need To Prepare Now
Do not wait for the enquiry letter. Organise these documents before you submit your claim. If HMRC opens an enquiry, you typically have 30 days to respond. That is not enough time to reconstruct evidence from scratch.
Written Contracts
You need a signed contract for each subcontractor engaged on R&D work. The contract should clearly state:
- The scope of work and deliverables
- That you own the intellectual property arising from the work
- The payment terms and rates
- That the subcontractor is not an employee (important for IR35 and employment status)
Timesheets Or Activity Logs
HMRC wants to see how much time each subcontractor spent on qualifying R&D activities versus non-qualifying work. Timesheets are the best evidence. If you do not have timesheets, project management logs, email records, or meeting notes can help. But timesheets are stronger.
Technical Narrative
Your R&D claim must include a technical narrative that describes the scientific or technological uncertainties you faced and how the project sought to overcome them. For subcontractor costs, the narrative should connect the subcontractor's work to specific technical challenges. Vague descriptions like "developed software features" will not pass scrutiny.
Invoices And Payment Records
Keep all invoices from subcontractors. HMRC may ask for a sample to verify the amounts claimed. If you paid in foreign currency, show the exchange rate used and the sterling equivalent.
Project Records
Emails, design documents, test results, and progress reports all help demonstrate that the work was directed and supervised by your company. HMRC wants to see that you controlled the R&D project, not the subcontractor.
How To Structure Your Response To An HMRC R&D Enquiry
If you receive an enquiry letter, do not panic. Follow a structured process:
- Read the letter carefully. HMRC will list specific documents and information they want. Respond to exactly what they ask for. Do not volunteer extra information unless it strengthens your position.
- Assign a lead contact. One person in your company should coordinate the response. This is usually the finance director or the accountant who prepared the claim.
- Gather evidence in order. Organise documents by subcontractor and by project. Use a clear index so HMRC can cross-reference your response against their questions.
- Write a covering letter. Summarise your response, confirm that all documents are provided, and state that you believe the claim is correct. Keep the tone professional and cooperative.
- Review with your accountant. Before sending anything, have your accountant review the response. An ICAEW qualified accountant can spot gaps or weak points that HMRC will exploit.
If your R&D tax credit claim was prepared by a third-party agent, involve them in the response. HMRC will expect the agent to explain the methodology used.
Common Mistakes That Worsen An Enquiry
Some errors turn a routine information request into a full compliance check. Avoid these:
- Missing deadlines. HMRC sets a response deadline, usually 30 days. Missing it can lead to penalties and a more intrusive enquiry.
- Inconsistent narratives. If your technical narrative says the subcontractor solved a specific technical problem but the contract describes routine development, HMRC will flag the inconsistency.
- Claiming costs twice. If your subcontractor also claims R&D relief on the same staff costs, both claims are invalid for those amounts.
- No evidence of direction. HMRC expects your company to direct and control the R&D work. If the subcontractor worked autonomously, the costs may not qualify.
- Overclaiming connected party costs. For connected subcontractors, the qualifying cost is capped at 65% of the subcontractor's relevant expenditure. Many claims get this wrong.
What Happens If HMRC Rejects Your Claim
If HMRC concludes that some or all of the subcontracted developer costs do not qualify, they will issue a closure notice amending your corporation tax return. This means:
- Your corporation tax liability increases by the amount of relief withdrawn
- Interest accrues from the original due date of the corporation tax
- Penalties may apply if HMRC finds careless or deliberate inaccuracies
You can appeal a closure notice. The first step is a statutory review by an HMRC officer not involved in the original enquiry. If that fails, you can take the case to the First-tier Tribunal (Tax Chamber). Most cases settle before tribunal, but you need professional representation.
If your claim is legitimate and properly documented, the outcome is usually a partial reduction rather than a full rejection. HMRC rarely denies an entire claim unless there is evidence of fraud or systematic misrepresentation.
Preventing An Enquiry In The First Place
You cannot completely prevent an HMRC enquiry. HMRC selects claims for review based on risk profiling, random sampling, and sector focus. But you can reduce your risk by following best practice:
- Use a qualified accountant who specialises in R&D claims. DIY claims are much more likely to be selected for review.
- Keep contemporaneous records. Write up technical narratives while the project is fresh. Do not reconstruct them months later.
- Be precise about subcontractor costs. Only include costs that directly relate to qualifying R&D activities. Do not inflate figures.
- Check connected party rules. If you use a connected subcontractor, ensure the contract is in place before work starts and that you understand the 65% cap.
- Review your claim before submission. Have someone independent check the numbers and the narrative for consistency.
For more on the fundamentals of what qualifies, read our R&D tax credits fundamentals guide.
Real Example: A Manchester Software Company's Enquiry
We worked with a software consultancy in Manchester's Northern Quarter that claimed R&D relief on £180,000 of subcontracted developer costs. HMRC opened an enquiry asking for contracts, timesheets, and a breakdown of qualifying activities.
The company had used three subcontractors. Two had signed contracts that clearly stated the company owned the IP. The third had a verbal agreement only. HMRC disallowed the costs for the third subcontractor because there was no written contract and no evidence that the company directed the work. The total reduction was £42,000 of the claimed relief, plus interest.
The lesson: written contracts are not optional. They are the minimum standard HMRC expects.
When To Get Professional Help
If you receive an HMRC R&D enquiry letter, contact your accountant immediately. Do not attempt to respond alone. The enquiry process is procedural, but the stakes are high. A poorly handled response can cost you thousands in lost relief, interest, and penalties.
If your turnover has grown significantly or your R&D claim has increased year on year, consider a pre-submission review with an accountant. This can identify weak points before HMRC does.
We handle R&D enquiries for clients across the UK, from our offices in Manchester, London, and Birmingham. If you need support, get in touch.
For a broader overview of R&D tax credits and how they interact with your corporation tax return, see our R&D tax credits blog category.