There are 103 cases in the UK according to official figures.
Last week there were 77 cases reported.
Scientists are urgently investigating to determine if the new stain is behind the surging rates of Covid in India.
Mr Johnson will update the nation on the latest information about the situation at 5pm tonight.
Yesterday Health Secretary Matt 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.”
However, the Health Secretary refused to give assurances the current vaccines being deployed across the country would be effective against the new variant.
Asked if the jabs would still work against the strain, the West Suffolk MP warned: “Of course we’re looking into that question as fast as possible but that is the core of my concern about the variant first found in India, is that the vaccines may be less effective in terms of transmission and, or in terms of reducing hospitalisation and death.
“It is the same concern that we have with the variant first found in South Africa.”
More to follow…