Boris Johnson will make a TV address tonight to set out “further steps” to combat the spread of COVID-19.
The prime minister is expected to speak at 8pm, while parliament will be recalled to sit on Wednesday.
A Number 10 spokesman said: “The spread of the new variant of COVID-19 has led to rapidly escalating case numbers across the country.
“The prime minister is clear that further steps must now be taken to arrest this rise and to protect the NHS and save lives.”
“He will set those out this evening.”
Earlier on Monday, Mr Johnson had warned there was “no question we will have to take tougher measures” and vowed the government would “do everything we can to keep the virus under control”.