The UK accreditation service (UKAS) is responsible for approving the 434 companies listed by the government as offering testing, but only 38 have so far been fully accredited - prompting complaints that holidaymakers are being exposed to "rip-offs". 

On Tuesday (10 August), images of "overflowing and unsecure" PCR test drop boxes from private firm Randox led to an angry backlash from consumers.

Speaking to The Telegraph, chief executive of Airlines UK, Tim Alderslade, said the travel testing regime was becoming "more untenable by the day". 

"No family should be priced out of a holiday because of a private market not functioning properly," he told the paper. "The review [of the testing firms for ’exploitative practices’] by the Competition and Market Authority is welcome but ministers need to go much, much further."

A UKAS spokesman reportedly said that, of 500 applications to date across both the travel and domestic markets, 350 had passed stage two and there had been 200 stage assessments, of which 38 had been fully accredited.

Huw Merriman MP said "passengers are being ripped off with expensive PCR tests" after claiming that only 5% of positive PCR tests had been genomically sequenced.