The health secretary has asked the competition watchdog to investigate the market for PCR tests amid concerns of “exploitative practices” and vastly different costs.

Sajid Javid wrote to the Competition and Markets Authority (CMA) requesting a “rapid high-level” review to protect travellers.

PCR tests, which use a swab to detect coronavirus on the tonsils and inside the nose, typically cost around £75.

However, travellers have complained of significant price differences and levels of service from the more than 400 firms which offer the tests.

“The cost of PCR testing can act as a barrier, especially for families who want to travel together,” Mr Javid said in his letter to CMA chief executive Andrea Coscelli.

“It is not right if some families experience yet further disruption unnecessarily because of practices in the market for private travel tests.”

The letter continued: “It is for these reasons that I am writing to you to ask you to conduct a rapid high-level review of the market for PCR travel tests to assess what action might be taken to ensure that consumers do not face unnecessarily high costs or other poor provision.”

He asked the CMA for immediate advice on how to “stamp out any exploitative behaviour in this market” ahead of an investigation and urged the watchdog to “take action to prevent such exploitation where you can under your existing powers”.

The health secretary also tweeted: “People should be able to go on holiday, whether it’s to see family or just to relax, without fearing excessive fees for PCR tests.”

A CMA spokesperson told Sky News: “We are aware of concerns about the evolving markets for COVID-19 tests for international travellers.

“We look forward to providing the Secretary of State with advice on how best to ensure that travellers have access to tests that are affordable and reliable.”

A list of companies and clinics offering COVID testing is published by the government, but many have reportedly not got full accreditation.

Some MPs and travel firms are pressurising ministers to scrap the costly tests and instead use the cheaper lateral flow tests.

Conservative MP Huw Merriman told BBC Radio 4’s PM programme that lateral flow tests were “much cheaper”.

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He added: “It’s effective, and then if that tests positive for COVID – and very few do when they come from abroad back to this country – then have a PCR and then have that sequencing.

He added: “And the reason I say that is because lateral flow tests can be a third of the price.”