Was/now pricing and reference prices on the shelf

In Great Britain there is no fixed number of days that a “was” price must have been charged. A comparison with a higher price is judged under the misleading-actions rules, and official guidance asks whether the average shopper would see it as a fair comparison.

The EU rule, the lowest price of the previous 30 days, does not apply here as law, but it is the benchmark many retailers with EU stores simply adopt.

This page sets out what the UK texts say, where they differ from the EU rule, and what a store with electronic shelf labels should log so it can defend a saving it advertises. It is information, not legal advice; the guidance was read in digest form and a solicitor’s review is pending. The wider picture is on the shelf price rules page.

What the UK rules say

Price comparisons fall under Part 4 of the Digital Markets, Competition and Consumers Act 2024. Section 226 defines a misleading action: false or misleading information about a product or any other matter relevant to a transactional decision, including true information presented in a misleading way, or an overall presentation likely to deceive the average consumer. The section does not mention price comparisons by name. A “was” price is caught because the saving it suggests is something a shopper relies on.

How that applies to a reference price is in the guidance rather than the statute. The CTSI guidance for traders on Business Companion, which replaced the government’s older Pricing Practices Guide, describes “was/now” prices as comparisons of an advertised price with a price the trader has previously charged. It warns that reference pricing “calls for a high level of trust and integrity”, and says a claimed saving must not be misleading or unfair and that you must be able to show it is genuine.

It sets no day count. Instead it gives factors:

• Period. A comparison is more likely to comply if it is made for the same period as the higher price, or a shorter one, and less likely if it runs for a materially longer period than the higher price was on offer.
• Recency. In one of the guidance’s worked examples, a travel agent compares with a price charged less than two months earlier with no intervening prices, and that is treated as acceptable. A price charged many months ago may no longer say anything about current value.
• Last price. Ideally the higher price is the last price the product sold at. Intervening prices make a claim less likely to comply.
• Real sales. You should be able to show significant sales at the higher price, or that it was a realistic selling price.
• Seasonality. Out-of-season reference prices are a concern.

The guidance’s own test is a plain one: would the average consumer think this is a fair comparison? Keep dated records of prices and sales so you can show it was.

How this differs from the EU rule

Article 6a of Directive 98/6/EC, added by the Omnibus Directive (EU) 2019/2161, requires any announced price reduction to state the previous price, defined as the lowest price the trader applied during a period of at least 30 days before the reduction. The Commission’s 2021 guidance adds that the lowest price includes earlier promotional prices, and that a percentage discount is calculated on that lowest price. The Court of Justice confirmed the second point on 26 September 2024 in Case C-330/23, Aldi Süd, where a leaflet showed 1.69 struck through next to 1.29 although 1.29 was already the lowest price in the previous 30 days.

	EU (Omnibus rule)	Great Britain
Fixed period	Yes, at least 30 days	None found
Reference price	Lowest price of that period, earlier promotions included	A genuine previous price, judged on period, recency and intervening prices
Percentage discounts	Calculated on the 30-day lowest price (C-330/23)	Must not mislead; no equivalent ruling read
Legal basis	Directive 98/6/EC, Art. 6a, as implemented by each state	DMCC Act 2024, Part 4, plus guidance

If you sell in the EU, including Ireland, your EU sales follow the 30-day rule. We have not checked how it applies in Northern Ireland. For a UK-only retailer the 30-day lowest price is not a legal requirement, but it is a simple internal standard: a price comparison that respects it is very unlikely to be thought unfair, and one rule across all stores is easier to configure than two.

A worked example, in pounds

The figures are invented to show the arithmetic; they come from no retailer.

A product sells at £4.00 for three weeks. On day 22 it drops to £3.50 for five days (a flash promotion) and on day 27 returns to £4.00. On day 31 the shop advertises “now £3.00, 25% off”.

Day	Price charged	Note
1 to 21	£4.00	Usual price
22 to 26	£3.50	Flash promotion
27 to 30	£4.00	Back to usual price
31	£3.00	Reduction advertised

Under the EU rule the reference would be £3.50, the lowest price of the previous 30 days, and the real saving 14.3% (50p of £3.50), not 25%. Under UK guidance the question is different: £4.00 was the last price and the one charged for most of the period, which points towards it being a fair comparison, but the five days at £3.50 are an intervening price, which the guidance treats as weakening a claim. A “25% off” headline built on £4.00 is the riskier choice, and a store would want to be able to explain it. The simplest defence is not to rely on the argument at all and to use the lowest recent price.

What the label system should record

Nothing in the UK texts mentions electronic labels. What they require is a result: a saving that is genuine, and the ability to show it. With prices changing across a store, that means a trustworthy record of what was charged and when, per store. The label price and the till price also have to agree, which is covered under shelf versus till.

A minimum record, one event per change of the price in force:

Field	Why
Article (SKU and barcode) and store or channel	Reference prices differ by point of sale
Final selling price including VAT	What the shopper sees, not the net ERP price
Start and end date and time	Rebuilds the price at any moment
Source of change (ERP, promotion, manual, rule) and user or process	Audit trail if a price is queried
Reason (usual price, promotion, clearance for damage or spoilage)	Separates real selling prices from clearance
Campaign ID	Tells a continuous reduction from successive promotions
Confirmation that the label showed the price	Proves what the shopper saw, not just what was sent

Two practical points. First, record what was applied, not what was scheduled: a cancelled promotion or a label that failed to update gives a false history otherwise. Second, keep the history for longer than any window you use, plus whatever period your business sets for handling complaints or trading standards queries. How long is a decision for your legal adviser; this page names no figure.

It also helps if the system warns when a planned reduction would show a different “was” price from the one on the label today, and refuses a percentage larger than the one worked out from your chosen reference. That is a data and process question, not a hardware one, so ask for it at selection and put it in the total cost of the system.

None of this stops you changing prices often. It governs how a reduction is advertised. Prices that vary by demand or customer raise separate questions, and electronic shelf labels as a technology change none of the rules here. Medicines are priced under their own rules, covered in the pharmacy regulation guide.

Checklist before a promotion

1. Identify the product and the store, and decide what counts as the same product.
2. Pick the reference price you will use and be able to say why: the last price charged, or the lowest in a recent period.
3. Check there were no intervening prices that make the comparison unfair, and no seasonal distortion.
4. Show the reference next to the reduced price on each label, and compute any percentage on that same reference.
5. Log the change with its source, reason and label confirmation.