More than 1,300 people were incorrectly told they had coronavirus after a lab error at NHS Test and Trace.
The department of health and social care said 1,311 people who were tested between 19 November and 23 November were wrongly told they had tested positive.
The issue was apparently down to an problem with a batch of testing chemicals, and the results were subsequently voided.
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.”
A total of 1,283 cases were removed from the government’s COVID dashboard on Friday as they had been reported in error.
As of 9am on Friday, government figures showed that 16,022 more people had tested positive for coronavirus in the UK – bringing the total to 1,589,301.
The troubled Test and Trace service has so far been given funding worth around £22 billion this financial year – around a fifth the annual budget of the NHS.
Boris Johnson has admitted there have been “teething problems” with NHS Test and Trace, but insisted it was value for money.