A big surge in infections has seen the number of cases of the Indian variant of coronavirus double in a week.
Cases across the UK have shot up from 520 last week, to 1,313 cases in the past seven days.
Most cases are in the North West of England, with some in London, Public Health England announced.
While there is no evidence that the strain is deadlier or can evade the vaccines, its rapid spread is worrying after months of falling case rates.
Yesterday Boris Johnson expressed these concerns and said that the mutant strain is of "increasing concern".
The Prime Minister said that there is "high likelihood" of a further surge in cases and hospitalisations this autumn, while refusing to rule out another lockdown.
"The end of lockdown is not the end of the pandemic," he said.
"The persistent threat of new variants, should these prove highly transmissible and elude the protection of vaccines, would have the potential to cause greater suffering than we had in January."
In a bid to tackle the outbreaks a new Surge Rapid Response Team is being deployed in Bolton, additional surge testing will shortly launch in areas such as Formby, and enhanced contact tracing is in place across England.
Ministers are also considering a range of options which could include bringing forward second doses for eligible groups.
To help identify variant cases, surge testing is already being deployed in 15 areas across England to suppress transmission, with more than 800,000 additional PCR test kits distributed.
Over 4,400 cases and over 14,000 close contacts have been traced and instructed to self-isolate.
Health and Social Care Secretary Matt Hancock said: “This data demonstrates why our swift and decisive measures are in place.
"Everyone has a part to play in controlling this variant, from participating in surge testing, to following the rules, to getting the jab.
"We are committed to working with local areas and deploying our world-leading genomic sequencing to get this variant under control.
"We are supporting areas where the cases of this variant are rising.
“We are monitoring the situation very carefully and will not hesitate to take further action if necessary."
The Surge Rapid Response Team in Bolton will include 100 nurses, public health advisers and environmental health officers, and will provide support to the local authority through door to door testing and encouraging residents to take a PCR test.
