London, Dec 12 (IANS): Britain reported another 21,672 Covid-19 cases, bringing the country's total to 1,809,455, according to the latest official figures.

The Covid-19 death toll in Britain rose by 424 to 63,506, the data showed.

Meanwhile, data from the Public Health England (PHE) showed Thursday that London recorded an average infection rate of 191.8 per 100,000 people for the week between November 30 and December 6, the highest in England, Xinhua reported.

PHE's data came after London mayor Sadiq Khan warned Londoners that the city risks moving from Tier 2 to the highest Tier 3 restrictions amid the surge in cases.

England is currently under a new three-tier system of Covid-19 restrictions that replaced the month-long lockdown which ended on December 2.

Under the system, shops are allowed to re-open across England, giving a Christmas bonanza to the struggling retail sector, but all bars and restaurants in the toughest Tier 3 areas remain closed.

The system puts about 98 per cent of England into Tier 2 and 3.

The system is due to be reviewed on December 16.

To bring life back to normal, countries such as Britain, China, Germany, Russia and the United States are racing against time to develop coronavirus vaccines.