Royal Mail is to raise wholesale postal prices by an average of 25%, with some tariffs rising by as much as a third, in a move that will hit the NHS and other large organisations that send high volumes of letters. The price increases, which take effect from 5 October, apply to bulk mail used for marketing letters, household bills and medical appointment notices, and come as the company, now owned by Czech billionaire Daniel Křetínský, continues to miss delivery targets set by regulator Ofcom.

The changes affect Royal Mail's wholesale customers, such as UK Mail, Whistl and Citipost, which sort and process mail for large organisations including banks, the NHS and HMRC. The NHS spent at least £100m on postage in 2024, meaning the increase could add several million pounds to its costs. Specific rises include a 36.1% increase for economy-service letters up to 100g and 11.4% for large advertising letters between 101g and 250g, while Ofcom has fined Royal Mail £37m since 2023 over missed delivery targets and launched a fresh investigation in June after nearly a quarter of first-class mail arrived late.