A total of 2,323 cases of the Indian coronavirus variant have been reported in the UK, the health secretary has said.
Delivering a COVID-19 statement in the Commons, Matt Hancock said 483 cases have been confirmed in Bolton and Blackburn with Darwen, where the variant is now the dominant strain of the virus.
Mr Hancock revealed there are 86 local authority areas where there are five or more confirmed cases of the variant – and said that surge testing will take place in Bedford following a rise in cases.
In Bolton and Bolton and Blackburn with Darwen, cases of the variant have doubled in the last week and are rising in all age groups.
"In Blackburn, hospitalisations are stable with eight people currently in hospital with COVID, and in Bolton 19 people are now in hospital with coronavirus – the majority of whom are eligible for a vaccine but haven’t yet had a vaccine," he said.
"This shows the new variant is not tending to penetrate into older, vaccinated groups and it underlines again the importance of getting the jab especially – but not only – amongst the vulnerable age groups."
On the wider vaccine rollout, it has been announced that 37-year-olds will be able to book a jab on Tuesday and 36-year-olds will be able to do some the same on Wednesday.
Mr Hancock was speaking as step three of Boris Johnson’s roadmap for easing restrictions in England came into effect.
People are now able to enjoy hugs with loved ones, indoor pints and meals and foreign holidays to a select number of destinations.
But the prime minister has urged the public to exercise a "heavy dose of caution" due to the threat of the Indian variant.
There are fears the variant – which could be as much as 50% more transmissible than the variant that emerged in Kent at the end of last year and led to England’s third lockdown – could delay the lifting of all legal limits on social contact on 21 June, step four of the roadmap.
Mr Hancock told Sky News at the weekend there is a "high degree of confidence" that the current COVID vaccines will protect against the Indian variant, but it could "spread like wildfire" among those who have not had a jab.
He repeated this in the Commons on Monday, telling MPs: "While we also don’t have the complete picture on the impact of the vaccine, the early laboratory data from Oxford University corroborates the evidence from Bolton Hospital and the initial observational data from India that vaccines are effective against this variant.
The health secretary said that while this was "reassuring", the early evidence suggests the variant is more transmissible than the Kent variant and this "poses a real risk".
Business Secretary Kwasi Kwarteng told Sky News earlier it is still "very likely" that step four will proceed as scheduled.
The PM’s spokesman has said the government is not yet in a position to make a definitive decision on whether the easing of restrictions will happen on 21 June.
And Downing Street said announcements on the future of social distancing, guidance on weddings and plans for domestic coronavirus "passports" could be delayed by the Indian variant.