More than 1,300 people were wrongly told they had coronavirus due to a lab error with NHS Test and Trace.
The Department of Health and Social Care (DHSC) said 1,311 people who took a test between November 19-23 across the UK were incorrectly told they received a positive result.
It said there was an issue with a batch of testing chemicals which meant their results were void.
A DHSC spokesman said: “Swift action is being taken to notify those affected and they are being asked to take another test, and to continue to self-isolate if they have symptoms.
“This laboratory error was an isolated incident and is being fully investigated to ensure this does not happen again.”
The DHSC did not comment on whether the error affected regional figures of infection rates.
On Friday, the DHSC said 1,283 cases were removed from the Government’s coronavirus dashboard as these tests were void and were reported in error by the laboratory as positive.
It said the error related to tests taken between November 11-23 in about 100 local authorities.
This meant the cumulative total number of people who tested positive was revised down on Friday, the DHSC said, but added: “Historic published date totals have not been changed.”
As of 9am on Friday, Government figures show there had been a further 16,022 lab-confirmed cases of coronavirus in the UK, bringing the total number of cases to 1,589,301.
Test and Trace has been beset with issues, with figures earlier this week revealing about four in 10 contacts of those who test positive for the virus are still not being reached.
The Prime Minister announced an extra £7 billion for Test and Trace in his winter plan on Monday in a bid to increase testing and improve contact tracing.
It takes the overall funding provided for Test and Trace this financial year to £22 billion – nearly a fifth of the entire annual NHS budget – which has been met with some criticism.
But Boris Johnson was adamant the system provided “value” for money although admitted there had been “teething problems”.
The Government said a further 521 people had died within 28 days of testing positive for Covid-19 as of Friday, bringing the UK total to 57,551.
Separate figures published by the UK’s statistics agencies for deaths where Covid-19 has been mentioned on the death certificate, together with additional data on deaths that have occurred in recent days, show there have now been 72,000 deaths involving Covid-19 in the UK.