The UK recorded 10,321 new Covid cases on Saturday as a government scientist warned a third wave is “definitely under way”.
There has been a 79 per cent rise in the highly contagious Delta variant in the past week and cases have been above 10,000 for three days in a row.
A total of 14 deaths were recorded on Saturday, taking the UK’s total to 127,970.
Professor Adam Finn, who advises the Government on the Joint Committee on Vaccination and Immunisation (JCVI), said a “third wave” of coronavirus infections “is definitely under way”.
The University of Bristol academic told BBC Radio 4’s Today programme: “It’s going up, perhaps we can be a little bit optimistic it’s not going up any faster, but nevertheless it’s going up, so this third wave is definitely under way.
“We can conclude that the race is firmly on between the vaccine programme, particularly getting older people’s second doses done, and the Delta variant third wave.”
The increase across the UK is being driven by younger age groups, many of whom have now been invited for a vaccination as the jab rollout extends to anyone aged 18 and over.
Hospital cases have almost doubled although most of those needing treatment have not had a vaccine.
Surge testing took place in south London on Saturday, with people being strongly encouraged to take a Covid-19 PCR test even if they had no symptoms.
The enhanced testing took place in Clapham, Brixton, Stockwell, West Norwood and Vauxhall.
So far, all the confirmed cases have been instructed to self-isolate and their contacts have been identified, the Department of Health and Social Care (DHSC) said.
Surge testing will also begin in Cumbria where everyone aged 12 to 30 who lives, works or studies in the area is strongly encouraged to take a PCR test, whether they are showing symptoms or not.
Those of school age will be offered testing at school.
The DHSC said people in these areas should continue to make use of free twice-weekly lateral flow tests alongside the PCR test as part of surge testing.