Holiday pay after Agnew: what Northern Ireland employers owe

Two routes to a claim, and the one that changes everything

A worker underpaid holiday pay in Northern Ireland can bring a claim two different ways. Under the Working Time Regulations (Northern Ireland), a complaint to an industrial tribunal ordinarily reaches back only three months from the date of claim. Under the Employment Rights (Northern Ireland) Order 1996, the same underpayment can instead be pursued as an unlawful deduction from wages — and that route lets a worker recover an entire series of deductions, provided the last one in the series fell within three months of the claim. That second route, the more generous one, is what Chief Constable of the Police Service of Northern Ireland and another v Agnew and others [2023] UKSC 33 was actually about.

What the Supreme Court decided on 4 October 2023

The case was brought by 3,380 police constables and 364 civilian PSNI staff who had been paid only basic pay for their annual leave despite regularly working overtime. The employer accepted the underpayment; the dispute was over how far back it had to go. The Supreme Court unanimously held three things that now govern every Northern Ireland holiday pay claim. First, a gap of more than three months between two underpayments does not, by itself, bring the series to an end. Second, a payment that happens to come out correct — because no overtime fell in that particular period — does not break the series either, if the method behind it was still wrong. Third, what actually counts as a single series is a question of fact in each case, not a fixed rule, with the common thread usually being the same underlying error repeated: holiday pay calculated from basic pay when it should have reflected normal pay.

The Court also confirmed that it is wrong to divide the reference period into equal calendar days when averaging a worker's pay — the calculation has to follow the pattern of pay actually received, not an arithmetic shortcut.

No two-year backstop — the gap that makes Northern Ireland different

In Great Britain, the Deduction from Wages (Limitation) Regulations 2014 cap most unlawful deduction claims, including holiday pay, at two years before the date of claim, for claims brought on or after 1 July 2015. Those regulations extend to England, Wales and Scotland only. They were never applied to Northern Ireland, and nothing has replaced them here.

The practical effect is that, once a series is established and shown to be unbroken, it can in principle reach back to the later of the worker's start date or 23 November 1998, when the Working Time Regulations (Northern Ireland) 1998 first gave workers the right to paid annual leave at all. Whether a given claim actually reaches that far is a question of evidence — you need payroll records covering the whole period, and a genuinely unbroken pattern of the same underlying error — but the legal ceiling that stops a GB claim at two years simply does not exist on this side of the Irish Sea.

What counts as "normal pay", and which weeks of leave it applies to

The Working Time (Amendment) Regulations (Northern Ireland) 2023, in force since 1 January 2024, set out in law what has to go into a week's normal pay for the purposes of the four weeks' leave granted under regulation 15 of the Working Time Regulations (Northern Ireland) 2016: commission payments intrinsically linked to the performance of tasks; payments tied to professional or personal status, such as length of service or qualifications; and other payments, including overtime, that have been regularly paid in the 12 weeks before the calculation date. Basic pay alone is not enough if any of those apply.

That enhanced calculation is a legal requirement for the first four weeks of leave specifically. The additional 1.6 weeks granted under regulation 16 is a domestic top-up on top of the EU-derived four weeks, and can lawfully be paid at the ordinary week's-pay rate. In practice most employers pay every week of the 5.6 weeks at the same enhanced rate, because running two different holiday pay calculations side by side causes more errors than it saves — but when you're sizing up historic exposure, it's the four weeks that the legal minimum actually bites on.

Worked example: an overtime-heavy trade business

Illustrative figures, real rules. Take a shopfitting firm in Coleraine with 14 staff. A fitter is contracted for 38 hours a week at £15 an hour — £570 basic weekly pay — and regularly works six hours of Saturday overtime at time-and-a-quarter, £18.75 an hour, adding £112.50 a week. That overtime has occurred in most weeks of every 12-week reference period since the fitter joined, which is exactly the pattern the 2023 amendment regulations describe as regularly paid.

Normal pay for the purposes of the four weeks' statutory leave is therefore £570 + £112.50 = £682.50 a week. If the firm has been paying holiday at the basic rate only, the shortfall is £112.50 for every week of leave taken. Across the four EU-derived weeks that's £450 a year. The fitter has been with the firm four years, the overtime pattern has been consistent throughout, and no correctly-calculated payment has ever broken the series — so the exposure for that one employee is roughly £1,800, and it has been sitting there, unclaimed but claimable, the whole time.

That's one employee. If nine of the firm's 14 staff have a broadly similar overtime pattern and an average four years' service, the rough scale of the firm's total exposure runs into the tens of thousands — not because any one payment was dramatically wrong, but because the same small error repeated, unbroken, for years.

The reference period: still 12 weeks here, not 52

Regulation 20 of the Working Time Regulations (Northern Ireland) 2016 sets the reference period for averaging a variable week's pay at the 12 weeks ending with the calculation date, excluding weeks with no pay or on sick leave and reaching back further to make the count up to 12. Great Britain moved to a 52-week reference period in April 2020; Northern Ireland has not followed, and the 12-week period is still what the law requires here. An employer can choose to run the calculation over 52 weeks instead, and many do to smooth out seasonal spikes, but only on the basis that it never produces a lower figure than the 12-week calculation would — see the Labour Relations Agency's note on holidays and holiday pay.

A 52-week reference period is coming, but it isn't law yet. The Department for the Economy has said it intends to legislate for the change as part of the wider Good Jobs Employment Rights Bill, which it expects to introduce before the end of the current Assembly mandate — see its oral statement of 28 April 2025. Until it passes, 12 weeks is the figure to work to.

Fixing the calculation doesn't erase what's already owed

These are two separate jobs, and it's worth keeping them apart. Switching to a correct, normal-pay calculation for the four weeks' leave from today stops the series growing any further — it does not retrospectively fix what has already accrued. Past underpayments remain claimable for as long as a worker can point to the last one falling within three months of a claim, which in practice means for as long as the wrong method is still being used somewhere in the business. A worker who wants to bring a claim has to notify the Labour Relations Agency for Early Conciliation within three months less a day of that last underpayment; missing that window is usually what closes off a claim, not the passage of years.

Your checklist for this week

• Pull payroll records for anyone who works regular overtime, commission linked to task performance, or shift/unsocial hours premiums, and check what rate their holiday pay was actually calculated at.
• If it's basic pay only, work out the gap between that and normal pay over a recent 12-week window, using the method above.
• Establish how far back the same pattern goes for each affected employee — that's your rough exposure, not a two-year GB-style estimate.
• Fix the calculation going forward for the four weeks under regulation 15 before doing anything else; this stops the series growing while you work out the rest.
• Decide, with proper advice, whether to address historic underpayment proactively or wait to see whether it's raised — both are legitimate business decisions, but only one of them is informed.

Buzz runs payroll and pension duties for clients across the region and this is exactly the kind of calculation we check as a matter of course, alongside the wider ways Northern Ireland employment law diverges from Great Britain — covered in full in employing people in Northern Ireland. Regulated legal advice on bringing or defending a claim needs a solicitor qualified in this jurisdiction; we'll refer you to one if it comes to that. Start at our Northern Ireland page, or the local pages for Coleraine and Belfast.