VAT errors rarely begin with a dramatic technical failure. More often, they start with a tax code, a manual workaround or a commercial change that no one revisits. In a large organisation, that decision may then be repeated across thousands of transactions before the resulting exposure becomes visible.
A regular VAT health check allows a business to look beyond whether its returns were filed on time and ask a wider question: do the VAT treatments, systems, processes and controls still reflect how the organisation operates today? The answer can reveal liabilities that need attention, but it may also uncover VAT that has been overpaid or underclaimed.
That question is increasingly important as HM Revenue & Customs (HMRC) focuses on the VAT gap. VAT investigations into medium-sized and large businesses rose by nearly a third in the year to March 2025. Timely compliance remains essential, but HMRC also wants to understand the control environment behind the figures and how a business prevents, detects and corrects errors.
Why VAT risk increases as a business grows
Size does not create a VAT problem in itself, but it magnifies the effect of inconsistency. A growing business may operate through several legal entities, sell into multiple jurisdictions, process high transaction volumes and rely on complex supply chains. VAT responsibility can also be spread across finance, tax, procurement, sales and operational teams.
- Different legal entities and VAT registrations
- New products, services and revenue streams
- UK and overseas supply chains
- Large volumes of automated transactions
- VAT decisions made across several teams
- Specialist knowledge held by only one or two people
Any one of these factors can create a gap between the VAT position a business believes it has and what happens in practice. If knowledge is not documented, a change in personnel can make that gap harder to identify and manage.
An absence of recent challenge from HMRC should not be taken as confirmation that everything is correct. A treatment may have been repeated for years without being selected for review, and an earlier HMRC visit may have focused on a different area.
A VAT health check provides a structured pause. It brings the right people together, documents how VAT decisions are made and identifies matters that require more detailed investigation.
What HMRC expects from VAT controls
HMRC is paying attention not only to whether a VAT error exists, but also to whether a business has effective measures to prevent or detect it.
In 2024, HMRC published Help with VAT compliance controls – GfC8, setting out its recommended approach to VAT accounting and compliance processes. The guidance follows the VAT data lifecycle from master data through accounts payable and accounts receivable to the VAT return. It emphasises clear ownership, documented controls and regular testing, and includes considerations relevant to Senior Accounting Officer (SAO) sign-off.
GfC8 is intended for UK VAT-registered businesses that use invoice accounting. It is not a one-size-fits-all checklist: the response should be proportionate to the organisation’s size and complexity.
Where an error emerges, evidence of clear responsibility, written procedures and control testing can help a business demonstrate reasonable care. The quality of the control environment may also be relevant to business risk ratings considered through HMRC’s Business Risk Review process and, for businesses in the SAO regime, annual certification.
What does a VAT health check examine?
The scope should reflect the business and the risks it faces. A broad VAT compliance review will usually consider:
- The VAT liability applied to sales and other income
- Input tax recovery, including partial exemption where relevant
- International VAT registrations and reporting obligations
- Reverse charge treatment on overseas purchases
- VAT return preparation, reconciliations and supporting records
- Master data, tax codes and enterprise resource planning (ERP) system logic
- Evidence supporting zero-rated exports of goods
- Roles, process documentation, control ownership and testing
A health check does not always need to cover the whole business. A targeted review may be more useful where management is concerned about a new income stream, overseas activity, input tax on a particular category of spend or the configuration of a specific system.
Common VAT issues uncovered by a health check
Because a VAT health check follows transactions and decisions through the business, it can expose issues that are not obvious from the VAT return totals alone. Examples include:
- New products or income streams introduced without a fresh VAT analysis
- Internal recharges or other revenue omitted from the VAT review process
- Reverse charge VAT not applied to relevant overseas costs
- Input tax claimed too cautiously or recovered in excess of entitlement
- Incomplete evidence for zero-rating exported goods
- Property income, cost recharges or other ad hoc transactions overlooked
- System coding that no longer matches the business’s activities
Each issue may create a liability, but the review should not focus only on tax owed. Input tax testing may identify missed recovery, while a wider process review can reveal ways to manage VAT more efficiently in future.
Business change is a key trigger for a VAT review
Many businesses begin with a workable VAT setup. Risk develops when commercial activity changes but the VAT map, system configuration or documented process does not change with it.
Expansion overseas may create new registration and reporting obligations. A new service or income stream may require a different VAT treatment. Acquisitions and restructures can affect VAT groups, intercompany recharges, processes and systems. The commercial decision may be entirely sound, but its VAT consequences are not always built into implementation.
A review is particularly valuable after:
- Rapid growth or a change in business model
- Launching a new product, service or revenue stream
- Entering a new country or changing supply routes
- An acquisition, disposal or group reorganization
- A finance-team restructure or change in key VAT personnel
- Implementing or materially changing an ERP system or tax engine
Taking stock at these points allows finance and tax teams to align the business’s current activities with its documented VAT position and actively manage anything that has been missed.
Technology can multiply good and bad VAT decisions
ERP systems, tax engines and automation can improve consistency and reduce manual effort. They can also repeat an incorrect VAT treatment at scale. One coding or master-data decision may affect thousands of transactions before an exception brings it to attention.
A system may have been configured correctly when it was implemented but no longer reflect new products, international activity or changes in the supply chain. Reviewing master data, VAT codes, exception reporting, manual adjustments and change controls can provide assurance that the technology remains fit for purpose.
The aim is not to inspect every transaction individually. It is to test the logic, ownership and controls that determine how transactions are treated.
What if the VAT health check identifies an error?
Early identification gives the business more control over the response. Correcting the position promptly can limit ongoing interest and help manage potential penalties where VAT is owed to HMRC.
Not every finding means additional tax is due. A review may show that output VAT has been overpaid, input tax has been underclaimed or VAT recovery could be improved. It can therefore produce refund opportunities as well as remediation actions.
How often should a business carry out a VAT health check?
As a practical baseline, businesses should consider an independent VAT review at least every four years because correction and claim periods can extend across the previous four years. A more frequent cycle may be appropriate for organisations experiencing rapid growth, international expansion, system change or regular changes to their business model.
Regular VAT health checks are also valuable before seeking investment or preparing a business for sale. VAT issues frequently surface during due diligence; identifying them earlier reduces the risk of unexpected liabilities affecting valuation, negotiations or transaction timetables.
Useful questions to ask include:
- When did the business last have an independent VAT review?
- Have recent commercial changes been assessed for VAT?
- Are the main VAT processes and controls documented, owned and tested?
- Does ERP coding still reflect current products, services and supply chains?
- Has the business checked whether it is recovering all VAT to which it is entitled?
If any of these questions are difficult to answer confidently, a VAT health check may be worth prioritising. Proactive review is usually less costly than correcting an issue after it has affected several years of transactions or been identified during an HMRC enquiry or corporate transaction.
How The VAT Consultancy can help
The VAT Consultancy works alongside in-house finance and tax teams to provide VAT risk management and control support. A review can cover the end-to-end VAT position or focus on a particular risk, process or business area. We can map processes and controls, review technical treatments, identify remediation and recovery opportunities, and assess whether systems support accurate VAT reporting.
Our team also supports businesses with ERP systems and tax engines, helping test the data and logic that drive VAT determination. To discuss a VAT health check tailored to the size, complexity and priorities of your business, please contact us
