Ruth Hutt said officials were confident they had traced most cases of the strain
But warned there was a risk it had spilled over into the wider community
More than 70 people in parts of south London have been forced to self-isolate
Some 44 cases of South African variant were found in Wandsworth and Lambeth
Department of Health is urging people in those areas to take Covid-19 tests
Are cases starting to rise after England s lockdown easing on March 29? UK s daily Covid cases go UP by nearly a third in a week to 3,568 while deaths halve to 13 - as England braves the snow and dashes to pubs to celebrate next step towards freedom
Statisticians added another 3,568 positive tests to the official tally, up 29% on last week s count of 2,762
Department of Health chiefs posted 13 more lab-confirmed victims 26 were recorded this time last week
Scientists have warned coronavirus cases will inevitably rise when restrictions are eased across Britain
England s lockdown was taken down another notch, with pubs and restaurants allowed to reopen outdoors
EXCLUSIVE: NHS data show 36 areas in England have vaccinated fewer than 60 per cent of over-50s, compared to 3,715 that have reached at least 90 per cent of those in high risk age groups.
Some 44 cases have been found in the Wandsworth and Lambeth boroughs, with a further 30 probable cases of the South African variant identified, the Department of Health and Social Care said.