How to spot and fix hidden payroll liabilities before your next payroll filing

Payroll is one of those areas where a small mistake can become an expensive problem very quickly. Over the years I’ve seen businesses discover hidden payroll liabilities at the worst possible time — the week before a quarterly PAYE filing, or when their bank balance is already stretched. In this article I’ll walk you through the common sources of those hidden liabilities, how to spot them early and practical steps to fix them before your next payroll filing. I’ll also give you a simple checklist and examples you can use straight away.

Why hidden payroll liabilities matter (and how they usually show up)

Hidden payroll liabilities are amounts you owe related to payroll that haven’t been recorded correctly in your accounts or payroll software. They often surface as unexpected entries on your bank statement, HMRC letters, or as penalties and interest. Typical consequences include cashflow shocks, late payment penalties, incorrect employee payslips and damage to staff trust.

They usually show up in a few predictable ways:

HMRC demands or late payment notices for PAYE, NICs or student loan deductions

Auto-enrolment pension shortfalls after a scheme reconciliation

Unpaid holiday pay, SMP/SAP overpayments or incorrectly treated termination payments

Discrepancies between payroll software reports and your bank or ledgers

Under-declared CIS deductions or subcontractor status mistakes

Quick checks to spot hidden liabilities before filing

Do these checks at least a week before your next submission. They’re quick but they catch a lot of problems.

Reconcile payroll to the bank: compare the total net pay, employer NICs, and pension payments in your payroll report to the amounts taken from your bank in the same period.

Review RTI submission statuses: check that all FPS and EPS submissions for the period are marked as accepted in your payroll software or HMRC account.

Scan HMRC correspondence: look for new Payment on Account, Coding Notice, or debt collection letters — these often indicate a missed liability.

Check pension provider statements: ensure contributions and employer payments match your payroll calculations and dates.

Compare payroll journal to ledgers: your nominal ledger or accountant’s bookkeeping should include payroll liabilities for PAYE, NICs and pensions.

Common sources of hidden payroll liabilities and how to fix them

Employer National Insurance (NIC) miscalculations

Problem: Employer NICs are often underestimated when an employee crosses thresholds mid-period, or when bonuses/overtime are paid outside the normal pay run.

Fix: Re-run the payroll for the relevant period with the correct gross pay including bonuses. If you use software like Xero, QuickBooks or Sage, use the back-pay/correction function to create an amendment FPS. If NICs were underpaid to HMRC, arrange payment immediately and report the correction in your next EPS/FPS as required. Keep a note explaining the correction for your records.

Auto-enrolment pension shortfalls

Problem: Pension provider reconciliations occasionally reveal missed employee or employer contributions — especially after pay increases or changes to qualifying earnings.

Fix: Contact the pension provider immediately to agree a reconciliation figure. You can backdate contributions for up to 3 months for many workplace schemes (and longer in some cases). Make sure you update your payroll template to reflect the right pensionable earnings and legal contribution percentages.

Student loan and attachment order errors

Problem: Student loan deductions, Child Maintenance, or Attachment of Earnings orders are missed when employee payroll records aren’t updated or when people change pay frequencies.

Fix: Check each employee’s payroll record for right plan type (Plan 1, Plan 2, Plan 4, Postgraduate) and thresholds. Reprocess any missed deductions and notify HMRC or the relevant agency. Where deductions were missed, you’ll likely need to collect from future pay or arrange a payment plan with the employee — document the agreement.

Mistaken employment status (contractors / CIS)

Problem: Misclassified contractors under PAYE vs CIS can leave you owing tax and NIC liabilities or CIS deductions that were not accounted for.

Fix: Reassess status with the contractor using HMRC’s employment status tools and correct historic payroll entries where needed. For CIS errors, reconcile gross payments and deductions with contractor invoices and rectify via the next CIS return or direct settlement with contractors.

Holiday pay accruals and untaken leave

Problem: Accrued holiday pay for workers and directors isn’t always tracked properly. When someone leaves or takes long periods of leave, there can be a big one-off liability.

Fix: Maintain a running holiday accrual in your payroll or accounting system (calculate on statutory or contractual rates as appropriate). When processing leavers, include accrued but untaken holiday in the final pay and report correctly for tax and NICs.

Step-by-step correction workflow to use now

Follow this simple workflow when you find a discrepancy:

Stop and gather evidence: payroll reports, bank statements, pension reconciliation, RTI submission receipts.

Calculate the exact shortfall: break down by PAYE, employer NICs, employee deductions and pensions.

Make adjustments in payroll software: create amendment FPS or use the software’s back-pay tools.

Notify affected employees: provide corrected payslips and a short written note explaining the change.

Pay HMRC and pension providers: arrange immediate settlement or agree a payment plan — don’t ignore the debt.

Document everything: why the error occurred, who approved the correction, and the date of correction.

Practical examples

Example 1 — missed bonus: A retail owner paid a year-end bonus off-payroll to save admin. When discovered, it should have had PAYE and NICs applied. Solution: Process a manual pay run adding the bonus gross, submit an amendment FPS for that pay period, and pay HMRC the correct liabilities.

Example 2 — pension reconciliation shows a missing month: You receive a reconciliation showing one month’s contributions missing. Solution: Confirm the missing amount with the pension provider, adjust payroll records, and make a backdated payment. Notify employees with the reconciliation summary.

Simple payroll liabilities checklist (use before each filing)

Check	Action
Bank reconciliation vs payroll totals	Match net pay, PAYE, employer NICs, pension payments
RTI submission status	Ensure FPS/EPS accepted; fix rejections
Pension provider reconciliation	Confirm contributions and dates
HMRC correspondence	Address letters and update liabilities
Employee record updates	Check student loan, attachment orders, tax codes
Holiday accruals	Verify accrual and final pay settlements

Tools and behaviours that prevent hidden liabilities

Some changes stop problems before they start:

Use payroll software that integrates with your bookkeeping (Xero, QuickBooks, Sage). That keeps ledgers and payroll in sync.

Run a short reconciliation after every pay run, not just at filing time.

Keep a single source of truth for employee data (HMRC codes, pension scheme IDs, student loan plan).

Schedule a quarterly payroll review with your advisor or accountant — catching small errors early avoids bigger bills later.

If you’d like, I can create a downloadable checklist or a template payroll reconciliation sheet tailored to your payroll frequency (weekly, fortnightly, monthly). Send over the payroll periods you use and I’ll produce a version you can drop straight into Excel or Google Sheets.