Public health experts have criticised the government's handling of the Immensa testing scandal amid spiking COVID-19 case numbers in affected areas.
An estimated 43,000 people were wrongly told they did not have COVID due to false positive PCR test results processed by the Immensa lab in Wolverhampton.
The false results were largely given to people living in the South West and Wales, and cases have since soared in these areas.
Downing Street has denied that the testing error has driven up infections, saying the figures are at least partly due to incorrect results being re-processed.
Experts however have warned that people will have spread the virus while unaware they had COVID.
Watch: NHS Test and Trace failed in its 'main objective', highly-critical report from committee of MPs finds
There are now nine UK areas with seven-day rolling case rates of more than 1,000 per 100,000 people. The areas and their most recent case rates are listed below.
Blaenau Gwent 1,326.8
Bath and North East Somerset 1,055.7
The map below shows the latest case rates in the UK by local area.
Downing Street denied that these rises can be put down to the Immensa scandal.
“In terms of the causes behind the increase in the South West, we’ve seen there was this lab error; I don’t believe that accounts for the increases we have seen,” said the prime minister's spokesperson.
“We know the South West was an area that did not previously have as high rates as other parts of the country, which may be a factor as well.”
However, experts have questioned that logic and challenged the government over their comments.
Deepti Gurdasani, senior lecturer in epidemiology at Queen Mary University London, said: "Anyone in government saying that the Immensa scandal has had no impact is blatantly lying.
"The case rates here are shocking. Higher than 4,500 per 100,000 per week in 10-14 yr olds in local authorities most affected. We need answers. Now."
Dr Zubaida Haque, member of Independent Sage, said the correlation between the labs and case numbers was clear.
"This is shocking: look at the spike in COVID rates in the 13 local authorities affected by Immensa Lab fiasco which gave out 10s of thousands of *false negative PCR* results," she said.
"How is there not a major independent inquiry into this scandal?? Jacob Rees Mogg is MP of one of these areas."
Professor Christina Pagel, also member of Independent Sage, said: "The government should be investigating on behalf of these areas instead of pretending that everything is fine.
"It's a total dereliction of duty towards your citizens."
Despite the failings, Immensa is continuing to process PCR tests for travellers who buy tests through their sister company Dante Labs, according to The Guardian.
Dante Labs is currently under investigation by the Competition and Markets Authority for its treatment of consumers on PCR tests.
Customers reported poor customer service, being refused refunds or delayed refunds, as well as unfair terms and conditions that may limit their rights.
Watch: Operations suspended at lab after false negative PCR tests at Wolverhampton laboratory