London, Dec 19 (IANS): Another 28,507 people in Britain have tested positive for Covid-19, bringing the total number of coronavirus cases in the country to 1,977,167, according to official figures released Friday.

The coronavirus-related deaths in Britain rose by 489 to 66,541, the data showed.

The figures were revealed as British Prime Minister Boris Johnson on Friday urged Britons to minimise their contact with those outside their household in the run-up to Christmas.

"If you are forming a Christmas Bubble, it's vital that from today, you minimise contact with people from outside your household," he said on Twitter.

"Everyone must take personal responsibility to avoid passing the virus on to loved ones this Christmas," he added.

Britain's coronavirus reproduction number, also known as the R number, has risen to 1.1 to 1.2, up from between 0.9 and 1.0 last week, according to the British government's Scientific Advisory Group for Emergencies (SAGE) on Friday.

The R number is one of many indicators scientists use to determine how fast Covid-19 is spreading in the country. If the R number is above one, it means the number of cases will increase exponentially.

Despite a surge in coronavirus cases, the British government has maintained its previous decision to relax restriction rules for Christmas, between December 23 to 27, allowing up to three households to get together in homes and places of worship in England.

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.