Research and Development (R&D) tax credits are a powerful government incentive aimed at encouraging UK businesses to innovate. These credits allow eligible companies to reduce their Corporation Tax liability or, in the case of loss-making businesses, receive a cash refund from HMRC. For businesses in Canary Wharf and across the UK, claiming R&D tax relief correctly can significantly improve cash flow and support further investment in technology, innovation, and staff development.

At ABM Chartered Accountants, our team helps businesses understand the eligibility criteria, calculate their R&D expenditure accurately, and ensure seamless submission of R&D claims through the CT600 tax return. In this guide, we explain step-by-step how to claim R&D tax credit on CT600, including SME and RDEC schemes, the latest HMRC requirements, and tips for avoiding common pitfalls.

What is an R&D Tax Credit?

R&D tax credits are a form of corporation tax relief available to UK companies investing in research and development activities. HMRC defines R&D as activities that seek to advance science or technology by addressing scientific or technological uncertainties.

Examples of eligible projects include:

Developing new or improved products, processes, or software
Creating innovative materials, designs, or prototypes
Enhancing operational processes with new technologies

It’s important to note that not all innovation qualifies. The work must involve uncertainty that a competent professional cannot resolve easily. Projects must also relate to the company’s trade and aim to benefit the business commercially.

Eligibility for R&D Tax Credits

To qualify, your company must meet the following conditions:

UK Limited Company: Only companies incorporated in the UK and subject to Corporation Tax can claim.
Qualifying R&D Activity: Activities must advance science or technology and involve technical uncertainties.
Expenditure on R&D: Costs must relate to staff, materials, software, subcontractors, or other eligible expenditures.
No Double Funding: The project cannot be receiving state aid or other subsidised expenditure for the same costs.

Types of R&D Tax Credit Schemes

There are different schemes depending on your company size, financial position, and accounting period:

1. SME R&D Tax Credit Scheme

Designed for small and medium-sized enterprises (SMEs), this scheme allows for higher relief rates than RDEC. Qualifying costs include:

Salaries of R&D staff
Materials and consumables
Subcontracted R&D costs

For loss-making SMEs, the scheme can generate payable cash credits, helping companies reinvest in growth.

2. RDEC (Research and Development Expenditure Credit)

Primarily for large companies or SMEs with subcontracted R&D, the RDEC is an above-the-line credit. This means it is shown as income in the profit and loss statement before tax and can be partially or fully offset against Corporation Tax.

3. Merged RDEC and ERIS (from April 2024)

From April 2024, the RDEC and SME schemes will merge into a single, unified scheme. The Enhanced R&D Intensive Support Scheme (ERIS) is for companies spending at least 30% of total expenditure on R&D, offering higher payable tax credits and enhanced relief rates.

Step-by-Step Guide to Claiming R&D Tax Credit on CT600

Claiming R&D tax relief requires careful preparation and accurate reporting. Here’s a step-by-step process.

Step 1: Identify Qualifying R&D Projects

Start by reviewing your company’s activities to identify eligible R&D projects. For each project, ask:

Does it seek to advance scientific or technological knowledge?
Are there uncertainties that a competent professional could not solve easily?
Are the costs directly related to the R&D work?

Keep detailed records of each project, including:

Project description
Objectives and technical challenges
Personnel involved and time spent
Costs incurred

A well-documented R&D report will strengthen your claim and is often requested by HMRC in the event of an enquiry.

Step 2: Track R&D Expenditure

Accurate tracking of costs is crucial. Eligible expenditure includes:

Direct Costs:

Staff salaries, pension, and National Insurance contributions for R&D activities
Materials and consumables used in the project
Software used exclusively for R&D

Indirect Costs / Qualifying Indirect Activities (QIA):

Utilities and maintenance for R&D facilities
Administration or laboratory support
Depreciation of R&D equipment

Subcontracted Work:

Costs paid to third parties for carrying out R&D tasks
Note: SMEs claiming subcontractor costs need to verify whether the subcontractor received state aid

Other Costs (from April 2023 onwards):

Cloud computing costs
Data licenses

Tracking should be methodical and detailed, as HMRC requires supporting evidence for all claims.

Step 3: Prepare the CT600 Tax Return

The CT600 is the official Corporation Tax return, and R&D claims must be included here.

Filing Options:

Using accounting software
Filing manually without software (our team can assist)
Through an accountancy firm in Canary Wharf, like ABM Chartered Accountants

On the CT600, ensure you:

Include total qualifying R&D expenditure in box 660
Include the enhanced expenditure in operating costs
Complete the CT600L supplementary form if claiming a payable tax credit

Step 4: Submit Additional HMRC Forms

Since August 2023, HMRC requires two additional forms:

R&D Claim Notification Form
- Required for first-time claimants or those who haven’t claimed in three years
- Must be submitted within 6 months of the end of the accounting period
Additional Information Form (AIF)
- Mandatory for all claims
- Includes details about projects, costs, and indirect activities
- Must be submitted before or alongside the CT600

Submitting these forms accurately is essential, as HMRC will not process the R&D claim without them.

Step 5: Calculate the Tax Credit

Once the CT600, CT600L, and supporting forms are complete, calculate your R&D tax credit:

For SMEs: Enhanced expenditure is usually 86% of qualifying costs (reduced from 130% pre-April 2023)
For RDEC: Above-the-line credit is 20% of qualifying expenditure
For ERIS: SMEs can claim up to 14.5% payable credit on enhanced expenditure

Also, consider PAYE/NIC caps, group company surrender, and other HMRC restrictions. This ensures your claim maximises relief while remaining compliant.

Step 6: Submit the CT600 and Supporting Documents

File the CT600 and CT600L electronically or by post
Attach:
- R&D report
- Claim Notification Form (if applicable)
- Additional Information Form (AIF)
- Supporting invoices and payroll records

After submission, retain all documentation for at least 6 years, as HMRC may request evidence during an enquiry.

Step 7: Record Keeping and Future Claims

Maintaining detailed records simplifies future R&D claims and ensures compliance with HMRC. Recommended records include:

R&D project logs and objectives
Time tracking for staff involvement
Subcontractor invoices and cost allocations
Cloud and software expenses

Benefits of Using an Accountant for R&D Claims

While some companies attempt to file CT600 without software, using a qualified accountant can help:

Identify all qualifying R&D projects and costs
Ensure correct preparation of CT600, CT600L, and AIF forms
Maximise your tax relief or payable credit
Reduce the risk of HMRC queries or rejections

If you’re in Canary Wharf or surrounding areas, choosing an accountancy firm in Canary Wharf, like ABM Chartered Accountants, ensures local, expert guidance tailored to your business.

Common Mistakes to Avoid

Claiming non-qualifying projects – only scientific or technological advances qualify
Missing supporting documentation – keep invoices, payroll, and project records
Failing to submit the AIF – HMRC will reject claims without it
Incorrect calculation of PAYE/NIC caps – especially for loss-making SMEs
Not updating claims for merged RDEC/ERIS schemes – effective from April 2024

Key Takeaways

Claiming R&D tax credit on CT600 can provide significant financial benefits for UK businesses. The process requires careful planning, accurate record-keeping, and knowledge of current HMRC rules.

Summary Checklist for Your R&D Claim:

Identify qualifying R&D projects
Track all eligible costs (direct and indirect)
Complete R&D claim notification form (if applicable)
Complete Additional Information Form (AIF)
Prepare CT600 and CT600L forms accurately
Calculate the tax credit, considering PAYE/NIC caps and group rules
Submit all forms and supporting documentation
Keep detailed records for HMRC enquiries

By following these steps and leveraging expert support, your business can maximise R&D tax relief and improve cash flow.

Why Choose ABM Chartered Accountants

At ABM Chartered Accountants, we specialise in helping businesses in Canary Wharf and beyond claim R&D tax credits efficiently and accurately. Our services include:

Comprehensive R&D project assessment
Preparing and filing CT600, CT600L, and AIF forms
Advising on eligible costs, PAYE/NIC caps, and group surrender rules
Ensuring compliance with HMRC requirements

Whether you want to file CT600 without software or need full accounting support, we provide expert guidance every step of the way.

Contact Us

Unlock the full potential of your R&D expenditure. Contact ABM Chartered Accountants, your trusted accountant in Canary Wharf, to discuss your eligibility and start claiming your R&D tax relief today.

FAQs

1. What is an R&D tax credit?

An R&D tax credit is a government incentive designed to reward UK companies for investing in innovation. It can reduce your Corporation Tax liability or, for loss-making companies, provide a cash payment from HMRC.

2. Who is eligible to claim R&D tax relief?

UK limited companies that carry out qualifying research and development projects can claim. Both SMEs and large companies can apply, but eligibility depends on project type, expenditure, and whether the work advances science or technology.

3. Can I file CT600 without software?

Yes, it’s possible to file CT600 without software, but using professional accounting tools or working with an accountancy firm in Canary Wharf ensures accuracy, compliance with HMRC rules, and avoids errors that could delay your claim.

4. What costs can be claimed under R&D tax credits?

Qualifying costs include staff salaries, subcontractor fees, materials, software, cloud computing, and certain indirect activities that support R&D, such as lab support or administration.

5. How long does it take for HMRC to process R&D claims?

Processing times vary: SME claims usually take around 28–45 days, while large company or RDEC claims can take over 120 days. Submitting accurate information, including the Additional Information Form, helps speed up the process.

How to Claim R&D Tax Credit on CT600