Boris Johnson is to address the nation tonight as concerns mount over the Indian variant of the coronavirus.
The Prime Minister will host a press conference at 5pm today.
It comes as India was added to the coronavirus "red list" in response to mounting concern about the number of cases there and the emergence of a variant.
Health Secretary Matt Hancock said so far 103 cases of the Indian variant had been identified in the UK.
Mr Hancock told MPs: "We've recently seen a new variant first identified in India. We've now detected 103 cases of this variant, of which again the vast majority have links to international travel and have been picked up by our testing at the border."
Mr Hancock said the samples have been analysed to see if the new variant has any "concerning characteristics" such as greater transmissibility or resistance to treatments and vaccines.
He added: "After studying the data, and on a precautionary basis, we've made the difficult but vital decision to add India to the red list."
The Department for Transport said the situation in India "has deteriorated with an extremely rapid rise in cases detected throughout April, which is accelerating".
It added that despite current travel measures, "there is a high volume of travel between India and the UK".
The Health Secretary highlighted the success of the vaccine rollout - with 10 million people now having received two doses - and falling hospital admissions and deaths.
But he told the Commons: "The biggest risk to our progress here in the UK is a new variant that the vaccine does not work as well."
In the same way that updated vaccines were deployed to tackle flu mutations, Mr Hancock said the Government was "ramping up plans for a booster shot to make sure our vaccines stay ahead of the virus".
