The number of cases of the variant in the UK has more than doubled in a week, from 520 to 1,313.
Most are in the northwest of England, where surge rapid response teams have been deployed, and there are cases in London.
There are calls for “surge vaccinations” of all younger adults in areas with the highest numbers of cases.
For lockdown to be lifted as planned on 21 June, the four tests on the government’s roadmap must have been met.
In a press conference on Friday, Boris Johnson warned the more virulent Indian variant of coronavirus could “pose a serious disruption” to plans to ease restrictions and “could make it more difficult” to end them on 21 June.
England is just three days away from reaching step three of the roadmap, with pubs and restaurants set to open their doors for indoor gatherings of six on 17 May.
But among the government’s four tests is that the “risks are not fundamentally changed by new variants of concern”.
There have been calls from experts to be cautious and NHS leaders warned on Friday that ministers must be prepared to hold fire on plans if the Indian variant spreads out of control.
Professor Paul Hunter, a viral disease expert from the University of East Anglia’s Norwich Medical School, said step four was “in doubt” and there could be a “huge number of cases” by June at the current rate of increase.
Vaccines minister Nadhim Zahawi said new local lockdowns or further national restrictions were an option to control the situation.
“We have got to break the cycle of infection, because one of those big tests was infection rates have to be suppressed, and the other big test is variants,” he told LBC radio on Friday morning.
“If those cause a problem, then the tests will fail. The four tests have to be met for 21 June.”
Mr Zahawi added that there was no evidence to suggest the Indian variant escapes the vaccines or causes more severe illness.
The prime minister is due to lead a press conference alongside Chris Whitty, the chief medical officer, at 5pm on Friday.
Mr Johnson’s spokesperson hinted that surge vaccines are being planned in hotspots, saying: “I can’t get ahead of the prime minister, you will hear from him yourself later this afternoon.”
The spokesperson added that Mr Johnson expects step three of lockdown easing to go ahead on Monday as planned.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies