Test Clients’ MTD Compliance With a Digital Tax Audit

HMRC enquiries have changed. With the rollout of digital tax reporting under Making Tax Digital (MTD), compliance checks are now data-led, faster and far more forensic. Automated risk profiling allows HMRC to look at submissions against real-time information, sector benchmarks and cross-tax data. For independent accountants and small practices, this means that MTD compliance is about being able to prove defensible processes and getting HMRC audit readiness right year-round.

The idea of a proactive mock audit should now be a routine part of your practice’s day-to-day operations. Rather than waiting for an enquiry letter, you should periodically test whether client systems, digital records and internal review procedures would withstand scrutiny. Strong compliance protects not just your clients, but your firm’s reputation.

The MTD Digital Compliance Checklist: Three Pillars of Digital Tax

Effective MTD compliance comes down to three pillars. Each needs structured review, documentation and ongoing oversight.

Verify digital record-keeping at source

The starting point of digital tax compliance is source data integrity. Every invoice, receipt and expense record must be captured digitally and stored within an accounting system. HMRC expects specific data points to be recorded electronically, including:

• Transaction date
• Value of supply
• VAT rate (where applicable)
• Income or expense category.

If your clients are still relying on paper records, scanned PDFs or ad hoc spreadsheets, their MTD compliance is at risk. If information is altered manually, the integrity of digital records is compromised. As their advisor, you’re the one expected to spot weaknesses before HMRC does. If digital links are broken or data is being manually altered between systems, the integrity of the records is compromised.

When you do a mock audit for MTD compliance, it’s a good idea to test if source documents are digitally captured at the point of transaction, if there is a single source of truth and whether changes are traceable and leave an audit trail. Disconnected spreadsheets are a common problem in small business systems. Even if bridging software is used correctly, fragmented processes will get in the way of your HMRC audit readiness.

Audit the ‘digital link’ continuity [H3]

One of the biggest issues in MTD compliance is the digital link. HMRC requires that data should flow between systems without manual copying and pasting. An API transfer, automatic import or linked cells in a controlled spreadsheet can all be part of a digital link. But, entering data manually breaks the rules. You must check the whole data journey:

Source transaction entry
Transfer to your accounting system
Adjustments of calculations
Submission to HMRC.

If your client or one of your employees exports data to Excel, makes changes manually and then re-enters the totals into software, the digital link has broken, which is a serious compliance issue. For full HMRC audit readiness, your mock exercise should include an end-to-end test submission environment where you trace sample transactions through the entire process and document the evidence. If challenged, you must show that your firm is actively compliant.

Ensure compliance with retention and accessibility rules [H3]

Digital tax requirements mean that you usually have to keep accounting records for five to six years, and, importantly, they must be easy to access. You should be able to retrieve historical records instantly, your backup procedures need to be documented and your access permissions should be secure but workable.

Cloud-based systems are typically the only viable way to guarantee accessibility and continuity. A local desktop file stored on a departing staff member’s device doesn’t allow for readiness. Retention compliance also needs regular reviews of access rights, backups and disaster recovery procedures.

High-Risk Areas in the Client’s Digital Records [H2]

Even when your digital systems are technically compliant, errors can still trigger enquiries. A proactive digital audit needs to identify high-risk transactional areas.

Reviewing disallowable expenses and adjustments [H3]

It’s not uncommon for small businesses to make mistakes when coding expenses. Mixed-use costs, like those for cars, cell phones or home office claims, need proportional adjustments. Entertainment expenses are also often not categorised correctly.

During your MTD compliance review:

Reconcile expense categories against supporting documentation
Confirm that adjustments are clearly recorded at End of Period Statement (EOPS) stage
Ensure digital links connect adjustments back to source records.

Traceability is very important for the accuracy of the digital record. You are less likely to win an enquiry if you make changes without proof. The right supporting documentation makes it easier for HMRC to do an audit and shows that you took reasonable care.

Payroll and Director’s Loan Account (DLA) reconciliation [H3]

Inconsistencies between payroll submissions, accounting records and personal tax are big HMRC triggers. It’s best to test whether:

RTI submissions reconcile with ledger payroll figures
Dividends align with distributable profits
Director’s Loan Accounts are cleared appropriately and supported by documentation.

When data-driven digital tax scrutiny comes into play, a misaligned DLA is especially risky. Automated systems can find discrepancies between submissions, so ensuring your reconciliation procedures are stronger makes MTD compliance more effective and reduces the risk of an enquiry.

Capital asset treatment and supporting evidence [H3]

Capital allowances claims need to be defensible. Ensure that you have a clear digital asset register, purchase invoices are attached digitally and your disposal procedures are accurately recorded. Without supporting documents, your readiness for an audit is reduced. If you want to be MTD compliant, you need to have digital proof. A well-maintained asset register shows disciplined governance and protects both you and your clients.

Leverage ICPA Resources for Audit Readiness [H2]

A proactive approach to compliance needs continuous technical awareness. Regulations, guidance and digital requirements change all the time. You can’t afford to operate in isolation.

Upskill your team with focused on-demand training [H3]

Digital tax rules means how you train your staff needs to go beyond basic software usage to include evolving MTD technical requirements, digital link rules, sector-specific risk areas and documentation standards for audit readiness. ICPA’s on-demand quarterly training courses provide structured, CPD-accredited updates in accounting standards and financial reporting designed for independent and small practices. Ongoing professional development makes sure your firm’s compliance efforts are aligned with HMRC expectations.

The immediate backup of technical support for ambiguous cases [H3]

Your mock audit will likely uncover some grey areas. Even an experienced professional can have trouble with complicated transactions, figuring out partial exemptions, residency issues or complex capital treatment. ICPA’s Technical Support service gives you immediate access to expert guidance when you’re unsure. Rather than second-guessing a treatment that could later be challenged, you can get expert insights before submission. This directly improves your audit readiness.

Embedding a Year-Round MTD Compliance Mindset [H2]

The shift to digital tax reporting has changed how compliance works. Errors are easier to detect, discrepancies are flagged automatically and manual workarounds are exposed. You need to do year-round mock audits that actively test systems, reconciliations, documentation standards and digital link integrity.

An ICPA membership gives you the support you need to strengthen your MTD compliance. When you use our expert guidance and structured learning, you move from defensive compliance to proactive control. In a digital reporting environment, preparation is professionalism. Join ICPA today to ensure your clients’ records and your firm’s reputation are secure.