Case rates in the South West have doubled in recent days after the error was spotted and five of the 10 worst-hit areas in England are now in the region.
At a Downing Street press conference, the Health Secretary said it s really important that people take a lateral flow test if they go to Christmas parties with elderly or clinically vulnerable people present.
The Department of Health s daily update showed there were 49,139 positive tests across the country in the last 24 hours, up by 15 per cent on the previous week.
At a gloomy Downing Street press conference, Sajid Javid warned that Covid cases could reach 100,000 a day this winter and urged people to take precautions to save Christmas.