A company considering making a claim for R&D tax relief can apply to HMRC for confirmation of how HMRC believes the rules will apply in the company’s circumstances. This is known as ‘advance assurance’.

From 18 May 2026, there are two types of advance assurance: 

• The targeted advance assurance service. This is a new service, giving eligible companies clarity on how HMRC believes the rules apply on specific, complex or high-risk areas of a potential claim for R&D tax relief.
• Full claim advance assurance service. This existing service is aimed at small companies making their first R&D claim, covers the entire claim for R&D tax relief rather than selected areas and applies for the first three accounting periods. 

A company cannot apply under both services for the same period or project. 

Targeted advance assurance

This is a pilot service, running to May 2027. As explained in an earlier article, changes to the advance assurance service were consulted on in March 2025.   

Under the service, SMEs (see HMRC’s guidance at CIRD 91300) can apply to HMRC for advance assurance on the following areas: 

• whether the project meets the definition of R&D for tax purposes (CIRD 81300);
• whether overseas expenditure qualifies for relief (CIRD150000);
• whether the company can claim R&D relief where work is contracted by one company to another (CIRD 160000); and
• whether the company qualifies for exemption from the pay as you earn and national insurance contributions cap (CIRD140000). 

Companies can make up to two applications for advance assurance. Each application can only include one project and one area of R&D tax relief.  

HMRC aims to process applications within 40 calendar days of the application being made, assuming all relevant information has been provided by the claimant. Where HMRC requires more information to assess the application, they will request this from the company. 

At the conclusion of its review, HMRC will either confirm that advance assurance has been granted or explain why it is unable to grant advance assurance.  

There is no mechanism to appeal against HMRC’s decision as this is a non-statutory service. However, a company can still make a claim for R&D tax relief where HMRC has declined its application for advance assurance. HMRC “strongly” advises the company to consider its position carefully before making a claim in these circumstances.  

HMRC’s guidance explains: 

• the conditions that the company must meet in order to make an application;
• how to make an application; and
• the information the company will need to provide when making its application.  

Full claim advance assurance 

This service is aimed at smaller companies, considers the full claim and, where advance assurance is granted, it covers the first three accounting periods.  

To make an application, it must be the case that the company: 

• is a SME (see above);
• has a turnover below £2m and fewer than 50 employees;
• has not claimed R&D tax relief previously. Where the company is part of a group, it must also be the case that none of the linked companies have claimed R&D tax relief before; and
• is planning to carry out R&D, or it has already carried out R&D, has not yet claimed R&D tax relief.  

HMRC’s guidance provides further details, including how to apply.