The latest scientific analysis has shown that the new variant of coronavirus spreading in the UK is much more infectious than the standard strain.
Researchers at Imperial College London say the new variant is spreading fast among children and younger people.
They have warned that even with a more strict lockdown in England the number of Covid cases would triple.
It came as the UK reported more than 50,000 new infections for the fourth day in a row.
The rise in cases is creating huge pressure on hospitals, with warnings that that bed capacity is running short and NHS staff are struggling to cope.
Reeta Chakrabarti presents BBC News at Ten reporting by health correspondent Dominic Hughes.
