Testing has been suspended at the lab responsible for incorrect Covid test results in Newbury and an investigation launched, the UK Health Security Agency (UKHSA) has said.

Results from PCR tests completed at Newbury Showground told people with Covid-19 that they were not infected over the last month.

NHS Test and Trace has suspended testing operations provided by Immensa Health Clinic Ltd, which has been awarded contracts worth £169m since the beginning of the pandemic.

Dr Will Welfare, public health incident director at UKHSA, said: “We have recently seen a rising number of positive LFD (lateral flow) results subsequently testing negative on PCR.

Read more: False negative PCR Covid tests at Newbury Showground

“As a result of our investigation, we are working with NHS Test and Trace and the company to determine the laboratory technical issues which have led to inaccurate PCR results being issued to people.

He continued: “There is no evidence of any faults with LFD or PCR test kits themselves and the public should remain confident in using them and in other laboratory services currently provided.

“If you get a positive LFD test, it’s important to make sure that you then get a follow-up PCR test to confirm you have Covid-19.”

An estimated 43,000 people in sites throughout the country may have been given wrong negative PCR Covid test results, UKHSA has said.

Test and Trace is contacting people who could still be infectious to advise them to take another test, while close contacts who are symptomatic will also be advised to take a test, as is already recommended.

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The Government awarded Immensa a £119 million contract in October 2020 to urgently “develop volume for PCR testing for Covid in line with test and trace requirements”, the contract shows.

The contract did not go to tender under rules allowing urgent responses to the pandemic.

A further £50 million was awarded to Immensa by the Government in a contract last September.

Immensa was incorporated as a company in the UK in May 2020 and according to the Immensa website, the firm was new to Covid testing.

Andrea Riposati, chief executive of Immensa, 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 for Health and UKHSA.

“We do not wish this matter or anything else to tarnish the amazing work done by the UK in this pandemic.”

Immensa is part of Dante labs, whose chief executive is Mr Riposati.

The Competition and Markets Authority (CMA) announced in September it was investigating Dante Labs over concerns it may be treating customers unfairly.

This included by not delivering PCR tests and/or results on time or at all, failing to respond to complaints or provide proper customer service, refusing or delaying refunds when requested and using terms and conditions which may unfairly limit consumers’ rights.