The update from Downing Street is scheduled for 5pm.
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The prime minister will be joined by Chief Medical Officer Chris Whitty and Chief Scientific Adviser Sir Patrick Vallance.
The press conference comes after data from the Office for National Statistics (ONS) infection survey showed the number of people testing positive for the new UK Covid variant has dropped in most parts of England since lockdown was announced.
The percentage of people testing positive with the new variant has decreased in the week ending 16 January 2021, particularly in London, the South East and the East of England.
"In other regions the percentage of new variant compatible positives has levelled off," it adds.
However, the ONS has found an estimated one in 55 people in private households in England had Covid-19 between January 10 and 16 2021.
This is the equivalent of 1.02 million people, or 1.88% of the population.
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