Most directors think of payroll as a transactional function. You run it, you pay people, you move on. Then a P11D is filed late, an employee challenges a pension contribution, or HMRC raises a Real Time Information (RTI) penalty notice — and suddenly the function nobody talks about is the one consuming everyone's time.
The visible penalties
HMRC penalties are well documented. A late RTI submission attracts a fixed penalty between £100 and £400 per month depending on headcount, and a separate late-payment penalty of 1% to 4% of the unpaid PAYE. These add up faster than most owners realise — a 25-employee business filing late for three months will see roughly £900 in fixed RTI penalties alone, before late-payment interest.
Auto-enrolment breaches are worse. The Pensions Regulator's fixed penalty is £400, but escalating notices reach £10,000 per day for the largest employers. Even SMEs face daily accrual once notices are issued.
The invisible costs that dwarf the penalties
The penalty regime is the smaller half of the problem. The larger half:
- Employee trust. One incorrect payslip — wrong tax code, missed overtime, mis-applied salary sacrifice — and your top performer starts updating their CV that evening. Recruitment to replace a £50k role typically costs £15k to £25k in fees, ramp time, and lost productivity.
- HMRC scrutiny. Repeated errors trigger compliance reviews. Once you are on the radar, you stay on it. Compliance reviews routinely cost £3,000 to £8,000 in advisory time, even when the underlying numbers turn out to be fine.
- Director liability. Failure to pay PAYE is one of the few areas where directors can be personally pursued via Personal Liability Notices under section 121C of the Social Security Administration Act 1992.
- Tribunal exposure. Unlawful deduction from wages claims have no qualifying period. One payroll error, one disgruntled leaver, one ET1 form.
The seven errors we see most often
- Wrong tax codes applied because the new starter checklist was skipped.
- Statutory sick pay miscalculated for irregular-hours workers.
- Holiday pay based on basic salary only, ignoring overtime and commission (Bear Scotland and subsequent case law).
- Pension contributions calculated on the wrong earnings band.
- Benefits in kind not reported on P11D or processed through payroll.
- Termination payments taxed incorrectly under the post-2018 regime.
- National Minimum Wage breaches from salary-sacrifice arrangements that push hourly pay below the threshold.
Any one of these can sit dormant for years and surface during a routine HMRC employer compliance review.
Designing the errors out
The fix is process, not effort. A robust payroll function has three pillars:
- A single source of truth. One HR system feeding payroll. Not three spreadsheets and a WhatsApp from the office manager.
- A monthly checklist with sign-off. New starters, leavers, salary changes, benefit changes, statutory payments — all confirmed before the payroll is run, not after.
- Independent review. The person preparing the payroll cannot be the only person checking it. Segregation of duties is not a banking-only concept.
Why outsourcing usually pays for itself
Our payroll bureau handles the full lifecycle — RTI submissions, auto-enrolment, P11Ds, P60s, year-end — with a senior reviewer signing off every cycle. The cost is typically £4 to £8 per payslip per month. For a 20-person business that is around £100 a month — less than a single tribunal hearing day at the lowest counsel rates. The maths is rarely close.
If you would like us to review your current payroll setup for the seven common errors above, request a payroll health check via our contact page. We do it free for businesses with 10 or more employees.