A Guide to HMRC’s Advance Tax Certainty Service for UK Investment Projects

In December 2025, HMRC released the much-anticipated draft guidance on Advance Tax Certainty Service (ATCS), a new process legislated under the Finance Bill 2025-2026. Scheduled to launch in July 2026, the ATCS aims to provide businesses with pre-emptive tax clearances, offering certainty on complex tax matters related to significant investment projects. This guidance introduces a streamlined process for gaining clarity on tax treatment for major UK projects, covering areas such as Corporation Tax, VAT, Stamp Duty Land Tax (SDLT), Income Tax, PAYE regulations, and the Construction Industry Scheme (CIS).

What is the Advance Tax Certainty Service (ATCS)?

The ATCS offers businesses an opportunity to receive binding tax clearances on major projects. By applying for clearance, companies can obtain certainty regarding their tax position, ensuring a smoother and more confident investment process.

The service is primarily designed for substantial UK projects with tax uncertainties that could significantly impact a company’s financial planning. This includes projects that involve large-scale investments, such as those exceeding £1 billion in qualifying expenditure, which may encompass tangible and intangible assets like plant, machinery, and software.

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Who Can Apply for ATCS?

HMRC has specified that a “qualifying person” can apply for a clearance. This can include any person who incurs the relevant expenditure or a person with control over it, such as an investment entity managing a joint venture or consortium.

Both UK-based and non-UK entities investing in the UK are eligible to apply for clearance. However, individuals involved in fraudulent activities, those who have received penalties for deliberate tax behaviour, and those whose previous clearance applications were declined are excluded from eligibility.

Financial Threshold and Project Scope

For a project to qualify for ATCS, it must involve at least £1 billion of new qualifying expenditure. This can include expenditure on assets such as plant, machinery, and software but excludes financing costs and equity investments, including mergers, acquisitions, and share buybacks. The £1 billion threshold applies to the entire life of the project or a group of similar projects with the same tax uncertainty.

It is important to note that the expenditure must relate to a new initiative rather than ongoing business activity. This ensures that routine operational expenses do not fall under the scope of the ATCS.

Key Steps in the HMRC’s Tax Clearance Process

Expression of Interest (EOI)

During the initial year of the ATCS, applicants will be required to submit an Expression of Interest (EOI). This will help HMRC manage capacity during the early stages of the service. Applicants must provide key project details such as scale, tax uncertainty areas, and deadlines. HMRC will prioritise projects with the highest levels of tax uncertainty and urgency.

Early Engagement Meeting

Once the EOI is reviewed, businesses are encouraged to request an early engagement meeting. This meeting allows companies to discuss the feasibility of the clearance process within their desired timeframes. HMRC aims for this meeting to take place within 10 working days of the initial contact.

Formal Application Submission

After the engagement meeting, businesses must submit a formal clearance application no later than 60 working days before the relevant filing date for the first tax return related to the project. The application must include:

• A detailed assessment of eligibility.
• An official business plan outlining project spend.
• A tax treatment analysis for the transaction.
  

HMRC will review the application for completeness and may request additional factual evidence or clarification.

Scoping and Planning Meeting

Once the application is accepted, HMRC will arrange a scoping and planning meeting within 21 working days. This meeting will define the clearance scope and prioritise tax areas so HMRC can provide certainty within a realistic timeframe.

HMRC Evaluation and Decision

After the planning meeting, HMRC will evaluate the application and provide regular updates. A clearance decision will typically be issued within 31 working days of the scoping meeting or 49 working days from receipt of the full application.

Post-Clearance Monitoring

Once a clearance is granted, it is valid for a defined period, usually up to five years or until the project concludes. The applicant must monitor compliance throughout this period, submitting an annual review to ensure assumptions remain valid. Failure to inform HMRC of material changes could result in the revocation of the clearance and the imposition of penalties.

Scope and Limitations of HMRC’s Tax Clearance Process

The ATCS covers complex tax matters but excludes certain areas:

• Routine tax issues or purely factual matters.
• Asset valuations and main purpose tests in certain regimes.
• Situations where there is already a clearance process in place, such as Advance Pricing Agreements.

Clearances issued under ATCS are binding for HMRC as long as the applicant adheres to the assumptions and conditions laid out. If the applicant deviates from the clearance, the tax authority may initiate an enquiry, and the clearance will no longer be valid.

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What Businesses Need to Know

To make the most of ATCS, businesses must maintain strong internal governance, ensure swift engagement with HMRC, and keep communication transparent. As the service progresses, HMRC will likely refine its process based on feedback and capacity constraints.

In the first year of operation, businesses will be encouraged to submit an EOI to manage demand. As the service matures, HMRC may lower the financial threshold or expand the scope to include additional tax issues.

Key Takeaways:

• The ATCS offers certainty on complex tax issues for major UK investment projects.
• Eligible applicants must demonstrate significant investment, with a minimum threshold of £1 billion in qualifying expenditure.
• The process involves multiple steps, including EOIs, early engagement meetings, formal applications, and ongoing monitoring.
• Post-clearance, businesses must remain diligent in ensuring continued compliance with the terms of the clearance.

At Apex Accountants, we offer expert advice and guidance on the advance tax certainty service process, ensuring your business complies with all requirements. Our team can help assess your eligibility, guide you through the application process, and assist in post-clearance monitoring. Contact us today for tailored tax planning and advisory services for your business’s investment projects.