The UK Competition and Markets Authority (CMA) has warned online businesses to incorporate compulsory delivery charges into advertised prices or face regulatory enforcement action.

In an open letter sent to online retailers, marketplaces, comparison platforms, and search engines ahead of the peak holiday trading period, the regulator stressed: "The first price consumers see should be the price they pay."

Under the Digital Markets, Competition and Consumers Act 2024 (DMCC Act), any invitation to purchase must show the complete cost up front.

This figure must include minimum mandatory delivery or collection fees, along with unavoidable taxes and charges.

The rule applies across the entire buying process, including paid advertising, product listings, shopping baskets, and checkout screens.

Where traders apply a flat delivery fee per basket, they must show the total price of the products, including the mandatory delivery or collection fee, throughout the shopping process. Organisations may also provide an itemised breakdown alongside the full sum.

If delivery charges are optional, businesses are required to outline the terms clearly from the outset instead of concealing them in drop-down menus, pop-up windows, or late checkout stages.

Commercial operators were urged to evaluate their websites, mobile applications, and marketing campaigns against the CMA209 price transparency guidance, published in November 2025, to correct missing fees and reduce regulatory exposure.

In its statement, the watchdog said: "Clear pricing that includes all the fees that people can’t avoid helps people compare offers confidently and choose the option that works best for them. Unexpected charges make it more difficult for consumers to understand and compare the true cost of products, including between different retailers."

The CMA pointed out that the DMCC Act provides powers to penalise pricing infringements with substantial financial penalties and to order customer redress.

Last month, the regulator formally classified Aldi and Lidl as "large grocery retailers".

That decision applied to Aldi Stores Limited, Lidl Great Britain Limited, and Lidl Northern Ireland Limited under the Groceries Market Investigation (Controlled Land) Order 2010.