Coronavirus figures in Barking and Dagenham are the worst in London.
Town hall leader, Cllr Darren Rodwell, has urged people not to think of themselves as "invincible" but to follow health and safety advice.
He warned the Christmas and New Year celebrations have taken their toll, but the peak of the pandemic won't be reached until the middle of this month.
Cllr Rodwell said: "The figures in Barking and Dagenham are the worst in London this week alone.
"You may think you're invincible, but none of us are. This virus kills. I can't say it enough. So please do the right things."
Cllr Rodwell was speaking on Monday, January 4, before prime minister Boris Johnson announced the country would go into a lockdown which is expected to last until the middle of February.
Mr Johnson said the new variant, which is up to 70 per cent more transmissible, was spreading in a "frustrating and alarming" manner.
He warned the number of Covid patients in English hospitals is 40pc higher than the first peak.
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Covid-19 case rates are increasing in all parts of England.
London has the highest regional rate of new cases of Covid-19 in England.
In the seven days to December 30 the rate stood at 934.3 cases per 100,000 people, up from 844.3 the previous week, and 531.5 two weeks ago.
Of the top 25 highest local rates in England, 11 are in the capital.
This includes Barking and Dagenham, which has highest rate in England (1,402.5) and Redbridge, which has the third highest rate (1,339.7).
Hospitals in London have a record number of patients with Covid-19. A total of 6,358 patients were in hospital in the capital as of 8am on January 3.
This is more than double the number two weeks ago (3,067 patients on December 20).
During the first wave of the virus, patient numbers peaked at 5,201 on April 9.
The figures come after Barking and Dagenham police were called to a number of suspected breaches of Covid-19 restrictions on New Year's Eve.
Up to 100 people were dispersed at a rave in Alfred's Way, Barking with 1,000 bottles of alcohol seized by police.
The organiser of one unlicensed music event in Kemp Road, Chadwell Heath, was fined £10,000 after police were called in on New Year's Eve.
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