Cases of the new Indian variant have more than doubled for the second week in a row with 1,313 cases confirmed – and some scientists fearing the B.1.617.2 variant will become dominant in the UK.
The clusters remain predominantly located in the North West and London, but health officials in Bedford have also raised alarm at an apparent spike.
In Blackburn, where multi-age surge vaccination will take place from Monday, as well as Bolton, the B.1.617.2 variant is thought to have driven a doubling of infections over the past seven days.
It has spread three times faster than previous variants of concern, such as that from South Africa, according to analysis by the Telegraph.
Experts are now urgently trying to establish to what extent the new Indian variant is more transmissible than the dominant one discovered in Kent last year, and whether it can get round the protection offered by vaccines.
Professor James Naismith, from the University of Oxford, said B.1.617.2 should be viewed as a country-wide problem. It will get everywhere, he said. We keep learning this lesson, but we know that this will be the case.
Another scientist, Professor Tom Wenseleers, at the University of Leuven, said the new variant could be out-competing others by up to 60 per cent.
In addition, Public Health England announced that case rates overall have increased across most areas of England, most sharply in the North West, followed by the East Midlands.
In the North West the rate was 32.6 cases per 100,000 people in the seven days to May 9, up from 25.5 the previous week, while in the East Midlands it increased from 23.1 to 29.8 over the same period.
Slight increases were also recorded in the East of England, London, North East and South West, which had the lowest rate at 13.1, up from 12.2. Yorkshire and the Humber recorded the highest rate at 40.5 cases per 100,000 people, down slightly from 42.5 in the previous week.