Campaigners have threatened Health Secretary Sajid Javid with legal action over a Covid testing fiasco which saw an estimated 43,000 people given false negative results.
The Government suspended test processing by Immensa Health Ltd last month after tens of thousands of Brits were wrongly told they didn't have the virus between September 2 and October 12.
The majority of people affected were in the South West of England, which now has the highest Covid rates in the country.
Recent figures from the Office for National Statistics found one in 40 people in the region had the virus, while London had the lowest proportion, at around one in 65.
The firm was awarded a £119m contract to run testing services from a lab in Wolverhampton last year, while Companies House documents show it had only existed since May 2020.
The Department for Health and Social Care (DHSC) admitted Immensa was still in the process of being accredited by UKAS, the independent regulatory body
The Good Law Project has now sent a pre-action letter to Mr Javid and the UK Health and Security Agency (UKHSA) demanding that he immediately terminates Immensa’s contracts, compensates the individuals affected and takes action to properly regulate private testing firms.
Jo Maugham, Director of Good Law Project said: "We don’t know why Government chose to sidestep established testing facilities in universities and hospitals to send £119m to a newly formed private company. But the consequences have been catastrophic.
"Many people are likely to have lost their lives. We want answers for their families and the tens of thousands of others whose lives have been blighted by the Government’s inexplicable disregard for public health."
The UK Health and Security Agency (UKHSA) said it was working with NHS Test and Trace and the company to determine what went wrong - and urged people to get retested.
NHS Test and Trace was contacting the people that could still be infectious to advise them to take another test.
Responding to the Good Law Project, a Department of Health spokesperson said: "The Immensa laboratory in Wolverhampton passed an independent quality audit overseen by NHS Test and Trace and is in the process of UKAS accreditation."
Following the announcement last month, Andrea Riposati, CEO of Immensa Health Clinic Ltd, said: "We are fully collaborating with UKHSA on this matter. Quality is paramount for us.
"We have proudly analysed more than 2.5 million samples for NHS Test and Trace, working closely with the great teams at the Department of Health and Social Care (DHSC) and UKHSA.
"We do not wish this matter or anything else to tarnish the amazing work done by the UK in this pandemic."
