The UK’s competition watchdog has ordered vets to cap prescription fees at £21 and proposed a price comparison website, after finding consumers had faced huge price rises and been “left in the dark” over bills.

The Competition and Markets Authority (CMA) said public satisfaction with the cost of services was “low” after an investigation into the £6.3bn market found “there is not strong competition between veterinary businesses”, with large chains dominant.

Written prescription fees will be capped at £21 for the first medicine and £12.50 for any additional medicines. The CMA had previously proposed a cap of £16.

Martin Coleman, the chair of the independent inquiry group, said: “Too often, people are left in the dark about who owns their practice, treatment options and prices – even when facing bills running into thousands of pounds.

“Our measures mean it will be made clear to pet owners which practices are part of large groups, which are charging higher prices, and for the first time, vet businesses will be held to account by an independent regulator.”

Legally binding measures include price lists, prescription fee caps, a price comparison website and mandatory branding by the large groups to increase competition and drive down prices.

Pet owners using a vet practice that is part of a larger chain can expect to see changes before Christmas, including standard price lists.

Practices must provide a written estimate in advance for any treatment expected to cost £500 or more, including aftercare costs, plus an itemised bill, excluding emergencies.

Average prices of vet services have risen “sharply and much faster than general inflation”, by 63% between 2016 and 2023, the watchdog found. It said it had not seen evidence of a strong link between price increases and investments in quality.

“We have seen internal documents from some LVGs [large veterinary groups] that link price increases to an expectation that pet owners will not react by purchasing less or switching away. We have also seen internal documentary evidence regarding pricing strategies at LVGs that are based primarily on non-quality factors,” it added.