How HMRC Connect 2.0 identifies P11D errors before you do

The P11D deadline is 6 July. Most accounting practices know this. What fewer realise is that HMRC does not wait until after the deadline to start looking for problems. HMRC Connect 2.0, the department's data analytics platform, has been cross-referencing employer data in real time for several years. By the time you submit, HMRC may already have flagged discrepancies in your client's records.

What is HMRC Connect 2.0?

HMRC Connect is a sophisticated data analytics system that pulls together information from dozens of sources and automatically identifies inconsistencies. The sources it uses include:

• Real Time Information (RTI) — every payroll submission your clients make
• P11D and P11D(b) submissions — benefit-in-kind declarations
• DVLA vehicle records — company cars registered to the employer
• Companies House — director details, shareholdings, company structures
• Land Registry — property ownership that may indicate beneficial loans or assets
• Bank data from third-party providers — via HMRC's legal powers under Schedule 23 FA 2011
• Social media and public sources — to corroborate lifestyle against declared income

HMRC does not publish exactly how Connect scores risk, but the pattern of what triggers compliance checks is well established from tribunal decisions and HMRC guidance.

The four most common P11D triggers

1. Company cars on DVLA records but absent from P11D

HMRC has access to DVLA data. If a vehicle is registered to a company but no car benefit appears on the P11D, that is an automatic flag. This is one of the most common sources of employer compliance checks. With approximately 20% of P11D errors relating to company car benefits, it is the single highest-risk category for most practices.

2. RTI payroll figures that do not match P11D Class 1A declarations

Connect compares the employer's RTI submissions with the P11D(b) declaration of Class 1A NICs. A mismatch triggers automatic follow-up: where benefits appear in payroll but no corresponding P11D(b) is filed, or vice versa. With mandatory payrolling of benefits-in-kind from 6 April 2026, this area is now significantly more complex.

3. Directors receiving benefits not declared as BIK

Companies House identifies directors and their connections to employer entities. Where a director receives private medical insurance, a beneficial loan, or other benefits that should be declared as benefits in kind, but the P11D shows no such benefit, Connect can flag it based on Companies House and DVLA cross-referencing alone.

4. Omitted or undervalued beneficial loans

Loans from close companies to directors and participators are particularly high risk. HMRC Connect cross-references company accounts, RTI data, and P11D submissions. An outstanding loan balance that should attract a beneficial loan charge — currently calculated at the official rate of 2.25% — that does not appear on a P11D is a known trigger.

What happens after a flag

When Connect identifies a discrepancy, HMRC may:

1. Send a compliance check letter requesting information about specific benefit categories
2. Open a full employer compliance review (formerly called a PAYE audit)
3. Issue a Notice of Determination for outstanding Class 1A NICs
4. Apply penalties under Schedule 24 FA 2007 for inaccurate returns — up to 100% of unpaid tax in cases of deliberate concealment

The statutory interest rate for late P11D(b) payments is currently 7.25% per annum. Penalties for careless inaccuracy start at 15% of the unpaid liability. For a client with £50,000 in undeclared BIK, that represents a material exposure on top of the primary liability.

What accounting practices can do now

The 6 July deadline gives practices a defined window to act. The practical steps are:

1. Identify which clients have company cars on payroll and verify that every vehicle is accounted for on the P11D. Cross-reference against the employer's fleet records, not just what the client reports.
2. Reconcile RTI submissions with P11D(b). The payrolling transition from 6 April 2026 means many employers are payrolling car benefits for the first time. Ensure that the P11D(b) reflects this correctly.
3. Review director loan accounts. Outstanding balances above the de minimis threshold (£10,000) that attract a beneficial loan charge need to appear on the P11D. Check each director's loan account balance as at 5 April 2026.
4. Check private medical insurance premiums. These are frequently omitted or undervalued, particularly where the employer pays premiums centrally and does not communicate the annual cost per employee to the payroll team.

The risk of doing nothing

HMRC Connect operates continuously. An employer compliance check can be triggered at any point, not just in the weeks after the P11D deadline. Practices that identify and correct errors proactively, before HMRC raises them, are in a significantly stronger position. Voluntary disclosure of errors typically attracts much lower penalties than errors discovered during investigation.

For practices managing ten or more employer clients, conducting a manual P11D review across the entire portfolio before 6 July is a significant undertaking. The review is clearly worth doing; the question is whether it can be done systematically enough to catch everything.

Lexendo's P11D Readiness Assessor runs a structured BIK assessment for each client, flags the categories most likely to attract HMRC attention, and calculates the Class 1A NIC exposure before the deadline. It does not replace professional judgement — but it makes the systematic review significantly faster.

The P11D filing deadline is 6 July 2026. Class 1A NICs are due by 19 July (cheque) or 22 July (electronic). Lexendo's P11D Readiness module is available to all subscribers.

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