Up to three quarters of new UK Covid cases could be of the Indian variant, Health Secretary Matt Hancock has said.
Public Health England data shows cases of the variant have risen by 3,535 to 6,959 since last week.
Mr Hancock told a Downing Street briefing that the government had always expected cases to rise as restrictions were eased.
But he said it was "critical" to monitor the link between cases and hospitalisations.
On Thursday, a further 3,542 coronavirus cases and 10 deaths within 28 days of a positive test were reported in the UK.
It is the second day in a row the number of new Covid cases has topped 3,000 - the first time infections have reached this level since mid-April.
Over the last seven days, cases are up 20.5% compared with the week before.
'Remain vigilant'
Mr Hancock told the briefing on Thursday: "The latest estimates are that more than half and potentially as many as three-quarters of all new cases are now of this variant.
"As we set out our roadmap we always expected cases to rise - we must remain vigilant."
Mr Hancock said the increase in cases was still focused in hotspots.
The PHE data found the worst-affected areas continue to be Bolton, Bedford, and Blackburn with Darwen, which have seen 1,354, 366 and 361 confirmed cases, respectively.
PHE added, however, that there are small numbers of cases of the variant in most parts of the country.
Mr Hancock said there was surge testing and vaccinations in the eight hotspot areas, and there was also increased testing in places where cases were lower but rising.
The health secretary urged people to get both vaccine doses, saying all of the evidence showed it was the best way to protect yourself, loved ones and the wider community.
Of the 49 people in hospital with Covid in Bolton only five had received both doses, he said.
Mr Hancock added that vaccines were "severing the link between cases and hospitalisations and deaths from coronavirus".
Dr Jenny Harries, chief executive of the UK Health Security Agency, said public health experts were "actively going out and finding cases so we do expect cases to rise", and that cases were expected to go up through increased socialising.
She told the briefing that when looking at patterns of cases, such as in London, "we've seen a bit of community transmission and then it's closed down again".
She said it was "on the cusp at the moment" over whether rising cases reflected the variant taking off or whether there was a rise because more cases were being hunted for and detected.
"On the good news, of course, we are not seeing that generally translating into increased cases of hospitalisation and definitely not into deaths," she said.
"So the key message there is... if we can hold it while the vaccination programme gets rolled out, we stand a much better chance of getting through this session."
The Indian variant is clearly becoming dominant in the UK, replacing the Kent variant that caused the deadly winter surge.
The figures quoted by the health secretary are skewed by the fact that the testing of positive cases for variants is heavily targeted towards areas where the variant is known to be spreading.
The bigger question, though, is to what extent the rise of this variant matters.
Overall, cases are going up - but this was expected at this stage of the easing because of the green light for indoor mixing.
A more infectious variant - as this one seems to be - will put even more upward pressure on infections.
So it comes down to two things - how much more infectious it is and to what extent the vaccination programme has weakened the link between cases and hospitalisations given over half of adults are still waiting for their second dose and a quarter have not had their first.
A very rapid surge in infections has the potential to cause real problems as it will allow the virus to find those that are still at risk.
There are plenty of reasons to hope that will not happen given how well advanced the vaccine programme is, how low infection levels are (we have one of lowest rates in Europe) and the arrival of warmer weather which should mean more time outdoors.
But as always with this virus nothing can be taken for granted.
The PM said he saw nothing "currently in the data" to suggest the government would have to delay unlocking.
But he added there were signs of an increase in the number of cases of the Indian variant.
Mr Johnson said it was important to understand to what extent the vaccine programme "interrupts the link" between infection, hospitalisation, serious illness and death.
Government scientists had always made clear that infection levels would increase as restrictions eased, particularly the resumption of indoor mixing.
But epidemiologist Prof Neil Ferguson, whose modelling was crucial to the decision to go into the first lockdown in March 2020, said the Indian variant meant the reopening of society was now "in the balance".
He told the BBC: "The key issue as to whether we can go forward is: will the surge caused by the Indian variant... be more than has been already planned into the relaxation measures?"
On 21 June, the government hopes to move to the final stage of its roadmap for lifting lockdown.
Step four would see all legal limits on social contact removed, nightclubs would reopen, and restrictions on large events and performances would be lifted.
Scientists advising the government are currently studying all relevant data since the last set of lockdown relaxations on 17 May.
One of the key claims made by Mr Cummings was that Mr Hancock lied about COVID-testing people before they returned to care homes in the early part of the pandemic.
Mr Cummings told MPs on Wednesday that the prime minister was furious to discover in April 2020 that untested hospital patients had been discharged to care homes, adding Mr Hancock had told the PM a month earlier they would be tested.
When asked about this claim, Mr Hancock told a Downing Street news conference: "Of course we committed, and I committed, to getting the policy in place but it took time to build the testing.
"We didn't start with a big testing system in the UK and then we built that testing system, and that's why the 100,000 target was so important because it really accelerated the availability of testing because when you don't have much testing we had to prioritise it according to clinical need."
More on Covid-19
When pressed if he had told the prime minister and Mr Cummings in March 2020 that they would all be tested, Mr Hancock said: "My recollection of events is that I committed to delivering that testing for people going from hospital into care comes when we could do it.
Please use Chrome browser for a more accessible video player
Special report: The killer in our care homes (May 2020)
"I then went away and built the testing capacity for all sorts of reasons and all sorts of uses, including this one, and then delivered on the commitment that I made."
After further questions, Mr Hancock added: "There'll be a time when we can go through all of this in great detail but the most important thing right now is that we've still got a pandemic."
Sky News political correspondent Joe Pike said that despite being repeatedly asked about the matter, Mr Hancock did not give specific answers and gave generalised replies.
Addressing the allegation that Mr Hancock had lied, the health secretary told the Commons today: "We followed the clinical advice on the appropriate way forward."
There was no requirement to test patients being discharged from hospital into a care home until 15 April 2020, government documents show.
Please use Chrome browser for a more accessible video player
'We took clinical advice on discharge plans'
Guidance to care homes dated 2 April 2020 said people who were COVID-19 positive could be discharged to care homes but should isolate once there.
It added: "Negative tests are not required prior to transfers/admissions into the care home."
And guidance in place until 13 March 2020 further stated community transmission was so low it was "very unlikely that anyone receiving care in a care home or the community will become infected".
There have been 36,275 deaths involving COVID-19 in care homes since the pandemic began, according to the latest figures from the UK's statistics agencies.
Adam Purnell, care and quality lead at Kepplegate Care Home in Lancashire, told Sky News: "Up until May last year we were being told testing wasn't a requirement for people moving into care homes from hospital.
"We were being told we were protected, but at every single webinar we were having, we were told it's not a requirement for asymptomatic people to be tested."
Image:Health Secretary Matt Hancock answers an Urgent Question in the Commons earlier
Mr Cummings yesterday accused the health secretary of repeatedly lying, being disastrously incompetent and claimed he should have been fired on multiple occasions during the pandemic.
Mr Hancock was attacked over failings around care homes policy, personal protective equipment (PPE) procurement and his public pledge on a target for 100k COVID tests a day by the end of April 2020 which caused disruption in Whitehall.
In the Commons earlier today, Mr Hancock insisted Mr Cummings's allegations were "unsubstantiated" and "not true", adding: "I've been straight with people in public and in private throughout."
Mr Cummings also said a second lockdown delay last autumn led to "tens of thousands" of extra deaths.
Please use Chrome browser for a more accessible video player
Cummings: 'Hancock should've been fired'
Boris Johnson, on a visit to a hospital on Thursday, avoided questions about whether he had confidence in Mr Hancock.
But he did deny Mr Cummings's claim that thousands of people needlessly died because of the prime minister.
Mr Hancock was asked if he has spoken to the prime minister about Mr Cummings's evidence to MPs and was asked if Boris Johnson has personally given him his reassurance that he has confidence in him as health secretary.
He replied: "The prime minister and I talk all the time and we're working incredibly hard on getting this vaccine rollout as broad as possible, making sure people get their second doses, and obviously very vigilant particularly to the areas of the country where cases are starting to rise as I've set out.
One of the key claims made by Mr Cummings was that Mr Hancock lied about COVID-testing people before they returned to care homes in the early part of the pandemic.
Mr Cummings told MPs on Wednesday that the prime minister was furious to discover in April 2020 that untested hospital patients had been discharged to care homes, adding Mr Hancock had told the PM a month earlier they would be tested.
When asked about this claim, Mr Hancock told a Downing Street news conference: "Of course we committed, and I committed, to getting the policy in place but it took time to build the testing.
"We didn't start with a big testing system in the UK and then we built that testing system, and that's why the 100,000 target was so important because it really accelerated the availability of testing because when you don't have much testing we had to prioritise it according to clinical need."
More on Covid-19
When pressed if he had told the prime minister and Mr Cummings in March 2020 that they would all be tested, Mr Hancock said: "My recollection of events is that I committed to delivering that testing for people going from hospital into care comes when we could do it.
"I then went away and built the testing capacity for all sorts of reasons and all sorts of uses, including this one, and then delivered on the commitment that I made."
After further questions, Mr Hancock added: "There'll be a time when we can go through all of this in great detail but the most important thing right now is that we've still got a pandemic."
Sky News political correspondent Joe Pike said that despite being repeatedly asked about the matter, Mr Hancock did not give specific answers and gave generalised replies.
Addressing the allegation that Mr Hancock had lied, the health secretary told the Commons today: "We followed the clinical advice on the appropriate way forward."
There was no requirement to test patients being discharged from hospital into a care home until 15 April 2020, government documents show.
Please use Chrome browser for a more accessible video player
'We took clinical advice on discharge plans'
Guidance to care homes dated 2 April 2020 said people who were COVID-19 positive could be discharged to care homes but should isolate once there.
It added: "Negative tests are not required prior to transfers/admissions into the care home."
And guidance in place until 13 March 2020 further stated community transmission was so low it was "very unlikely that anyone receiving care in a care home or the community will become infected".
There have been 36,275 deaths involving COVID-19 in care homes since the pandemic began, according to the latest figures from the UK's statistics agencies.
Adam Purnell, care and quality lead at Kepplegate Care Home in Lancashire, told Sky News: "Up until May last year we were being told testing wasn't a requirement for people moving into care homes from hospital.
"We were being told we were protected, but at every single webinar we were having, we were told it's not a requirement for asymptomatic people to be tested."
Image:Health Secretary Matt Hancock answers an Urgent Question in the Commons earlier
Mr Cummings yesterday accused the health secretary of repeatedly lying, being disastrously incompetent and claimed he should have been fired on multiple occasions during the pandemic.
Mr Hancock was attacked over failings around care homes policy, personal protective equipment (PPE) procurement and his public pledge on a target for 100k COVID tests a day by the end of April 2020 which caused disruption in Whitehall.
In the Commons earlier today, Mr Hancock insisted Mr Cummings's allegations were "unsubstantiated" and "not true", adding: "I've been straight with people in public and in private throughout."
Image:Dominic Cummings attacked the health secretary during more than seven hours of testimony
Mr Cummings also said a second lockdown delay last autumn led to "tens of thousands" of extra deaths.
Boris Johnson, on a visit to a hospital on Thursday, avoided questions about whether he had confidence in Mr Hancock.
But he did deny Mr Cummings's claim that thousands of people needlessly died because of the prime minister.
Mr Hancock was asked if he has spoken to the prime minister about Mr Cummings's evidence to MPs and was asked if Boris Johnson has personally given him his reassurance that he has confidence in him as health secretary.
He replied: "The prime minister and I talk all the time and we're working incredibly hard on getting this vaccine rollout as broad as possible, making sure people get their second doses, and obviously very vigilant particularly to the areas of the country where cases are starting to rise as I've set out.
Up to three quarters of new UK Covid cases could be of the Indian variant, Health Secretary Matt Hancock has said.
Public Health England data shows cases of the variant have risen by 3,535 to 6,959 since last week.
Mr Hancock told a Downing Street briefing that the government had always expected cases to rise as restrictions were eased.
But he said it was "critical" to monitor the link between cases and hospitalisations.
On Thursday, a further 3,542 coronavirus cases and 10 deaths within 28 days of a positive test were reported in the UK.
It is the second day in a row the number of new Covid cases has topped 3,000 - the first time infections have reached this level since mid-April.
Over the last seven days, cases are up 20.5% compared with the week before.
'Remain vigilant'
Mr Hancock told the briefing on Thursday: "The latest estimates are that more than half and potentially as many as three-quarters of all new cases are now of this variant.
"As we set out our roadmap we always expected cases to rise - we must remain vigilant."
Mr Hancock said the increase in cases was still focused in hotspots.
The PHE data found the worst-affected areas continue to be Bolton, Bedford, and Blackburn with Darwen, which have seen 1,354, 366 and 361 confirmed cases, respectively.
PHE added, however, that there are small numbers of cases of the variant in most parts of the country.
Mr Hancock said there was surge testing and vaccinations in the eight hotspot areas, and there was also increased testing in places where cases were lower but rising.
The health secretary urged people to get both vaccine doses, saying all of the evidence showed it was the best way to protect yourself, loved ones and the wider community.
Of the 49 people in hospital with Covid in Bolton only five had received both doses, he said.
Dr Jenny Harries, chief executive of the UK Health Security Agency, said public health experts were "actively going out and finding cases so we do expect cases to rise", and that cases were expected to go up through increased socialising.
She told the briefing that when looking at patterns of cases, such as in London, "we've seen a bit of community transmission and then it's closed down again".
She said it was "on the cusp at the moment" over whether rising cases reflected the variant taking off or whether there was a rise because more cases were being hunted for and detected.
"On the good news, of course, we are not seeing that generally translating into increased cases of hospitalisation and definitely not into deaths," she said.
"So the key message there is... if we can hold it while the vaccination programme gets rolled out, we stand a much better chance of getting through this session."
The PM said he saw nothing "currently in the data" to suggest the government would have to delay unlocking.
But he added there were signs of an increase in the number of cases of the Indian variant.
Mr Johnson said it was important to understand to what extent the vaccine programme "interrupts the link" between infection, hospitalisation, serious illness and death.
Government scientists had always made clear that infection levels would increase as restrictions eased, particularly the resumption of indoor mixing.
But epidemiologist Prof Neil Ferguson, whose modelling was crucial to the decision to go into the first lockdown in March 2020, said the Indian variant meant the reopening of society was now "in the balance".
He told the BBC: "The key issue as to whether we can go forward is: will the surge caused by the Indian variant... be more than has been already planned into the relaxation measures?"
On 21 June, the government hopes to move to the final stage of its roadmap for lifting lockdown.
Step four would see all legal limits on social contact removed, nightclubs would reopen, and restrictions on large events and performances would be lifted.
Scientists advising the government are currently studying all relevant data since the last set of lockdown relaxations on 17 May.
Up to three quarters of new UK Covid cases could be of the Indian variant, Health Secretary Matt Hancock has said.
Public Health England data shows cases of the variant have risen by 3,535 to 6,959 since last week.
Mr Hancock told a Downing Street briefing that the government had always expected cases to rise as restrictions were eased.
But he said it was "critical" to monitor the link between cases and hospitalisations.
On Thursday, a further 3,542 coronavirus cases and 10 deaths within 28 days of a positive test were reported in the UK.
Over the last seven days, cases are up 20.5% compared with the week before.
'Remain vigilant'
Mr Hancock told the briefing on Thursday: "The latest estimates are that more than half and potentially as many as three-quarters of all new cases are now of this variant.
"As we set out our roadmap we always expected cases to rise - we must remain vigilant."
Mr Hancock said the increase in cases was still focused in hotspots.
The PHE data found the worst-affected areas continue to be Bolton, Bedford, and Blackburn with Darwen, which have seen 1,354, 366 and 361 confirmed cases, respectively.
PHE added, however, that there are small numbers of cases of the variant in most parts of the country.
Mr Hancock said there was surge testing and vaccinations in the eight hotspot areas, and there was also increased testing in places where cases are lower but rising.
The health secretary urged people to get both vaccine doses, saying all of the evidence showed it was the best way to protect yourself, loved ones and the wider community.
Of the 49 people in hospital with Covid in Bolton only five had received both doses, he said.
The PM said he saw nothing "currently in the data" to suggest the government would have to delay unlocking.
But he added there were signs of an increase in the number of cases of the Indian variant.
Epidemiologist Prof Neil Ferguson, whose modelling was crucial to the decision to go into the first lockdown in March 2020, said the reopening of society is now "in the balance".
He told the BBC: "The key issue as to whether we can go forward is: will the surge caused by the Indian variant... be more than has been already planned into the relaxation measures?"
On 21 June, the government hopes to move to the final stage of its roadmap for lifting lockdown.
Step four would see all legal limits on social contact removed, nightclubs would reopen, and restrictions on large events and performances would be lifted.
Scientists advising the government are currently studying all relevant data since the last set of lockdown relaxations on 17 May.
The number of people with coronavirus in the UK has gone up by 3,542 in the latest 24-hour period, and another 10 people have died with COVID-19, government figures show.
Yesterday, a total of 3,180 cases were reported, with another nine coronavirus-related deaths.
Today's daily infections figure is the highest since 12 April when 3,568 cases were reported.
It comes as 236,119 people had a first dose of a COVID vaccine on Wednesday, taking the total to 38,614,683.
And 427,458 had their second jab on Wednesday, meaning 24,043,956 people are now fully vaccinated in the UK.
Since the pandemic began, a total of 127,758 people have died within 28 days of testing positive for COVID-19, according to government figures.
More on Covid-19
There have now been 153,000 deaths registered in the UK where COVID-19 was mentioned on the death certificate, data published by the Office for National Statistics show.
Boris Johnson has avoided answering questions on Dominic Cummings's explosive allegations - but suggested some claims were not based on reality.
Mr Johnson sidestepped questions about the claims - including that he is not fit to be PM - during a visit to a hospital on Thursday by saying he was "getting on with the job of delivering the roadmap".
He did not say whether he has confidence in Health Secretary Matt Hancock, who took much of Mr Cummings's flak, but said: "I think some of the commentary I've heard doesn't bear any relation to reality."
Michael Gove has said there was not an "ironclad" link between the 21 June date earmarked for the next stage of the roadmap out of lockdown and the possible introduction of COVID status certification.
The Cabinet Office minister told MPs: "People have quite rightly linked COVID status certification to stage four. There's no absolute necessary ironclad inviolable link between the two.
Please use Chrome browser for a more accessible video player
'The health secretary should have been fired'
Please use Chrome browser for a more accessible video player
Matt Hancock: 'allegations are not true'
"But, naturally, as we contemplate reopening at stage four, people will understandably want to know what our approach towards certification will be and how that will operate."
