Private COVID-19 testing companies will face £10,000 fines for taking advantage of holidaymakers as 91 are removed from the government’s approved list following a review.

Health Secretary Sajid Javid said following a review by the Competition and Markets Authority into the private COVID testing market, 135 providers have also had their inaccurate prices corrected.

“They will be removed from the list if they advertise misleading prices again,” he said.

“It is completely unacceptable for any private testing company to take advantage of holidaymakers and we are taking action to clamp down on cowboy behaviour.”

Mr Javid asked the competition watchdog a month ago to investigate the PCR test market over concerns of “exploitative behaviour” and vastly different costs to travellers who must take the tests on return to the UK.

Passengers complained of significant price differences and levels of service from the more than 400 firms offering the tests.

Some were failing to send out the tests on time or were not returning the results in time while others were changing their names so they appeared at the top of the alphabetical list.

The government has a list of companies and clinics offering COVID testing, but many lack full accreditation and more than 100 outlets in August were charging £200 or more.

Typically, the tests cost £75.

Mr Javid added: “Through our regular reviews and spot-checks, we have identified even more providers that were messing around with costs and have now removed 91 providers from Gov.uk and corrected inaccurate prices of 135 private providers who will be removed from the list if they advertise misleading prices again.

“From 21 September, in order to ensure travel test providers are performing to a high legalised standard, there will be tough new penalties for companies that fail to follow the law, including fixed fines of up to £10,000.”

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Analysis of the list by the Liberal Democrats showed just 11% of the providers offered tests for under £50, with the cheapest offering prices ranging from £20.

Some 24% of the providers were charging more than £200 – with the Mayfair GP clinic listed as £575, although its own website said prices start at £399.

All passengers arriving from green list countries, and people fully vaccinated in the UK and a few other nations entering from amber list countries, have to take a test on the second day after arriving in the UK.

Those arriving from amber list countries who are not fully vaccinated, or were vaccinated in countries not on the approved list, must take tests on day two and eight in the UK.

They must be purchased from a private provider before travelling.