In August, Lord Tyrie criticised the CMA and the government for their management of the tests. He told the BBC that the problem has resurfaced since the summer due to the government’s "carelessness".

"It was a scandal waiting to happen and it is now happening and it needs very urgent action if we’re to have to have a reasonable chance of protecting thousands of consumers," he added.

"To allow this to continue over the peak Christmas period would be scandalous. Other countries seem to have done better - we’ve got to try harder".

During the summer, health secretary Sajid Javid launched an investigation with the CMA into the market. A number of firms have since been removed from the official list of testing providers.

"It appears that some of the worst practices: misleading online advertisements; overpricing; unacceptably poor service among them, are still widespread," Lord Tyrie added.

A spokesperson for the government told the BBC it monitors issues raised by the public and takes "rapid action" if appropriate.

This action has, according to the source, included the removal of companies from the approved list on the government’s website.

"We’ve been clear that it is unacceptable for any private testing company to take advantage of holidaymakers," the spokesperson added.