One of the worst affected areas in England only saw a “very minor and short-lived impact” on transmission during the national lockdown.
Dr Mark Ansell, director of public health for Havering Council, said: “Our rates were 379 per 100,000 yesterday, so that is double the London average, which itself is higher than the England average.
“So, very much aware of the seriousness of our situation.”
He said the highest rates were among working-age adults but he warned the rate among older residents was rising.
On whether imposing Tier 3 restrictions on London would drive down transmission in the borough, Dr Ansell told BBC Radio 4’s Today programme: “I think most of the transmission is in the home.
“I think the recent lockdown had a very minor and short-lived impact locally in terms of a lot of our residents are working in health and social care.
“A lot of them are self-employed or they are in small, medium-sized sort of enterprises, so they work, they need to work, and they need to keep working to maintain their financial viability.”
He added: “The work at home sort of message that has benefited some other parts of London doesn’t necessarily have a great impact in Havering and the measures need to be focused on the needs of the particular communities.”
Havering, in east London, has the 10th highest infection rate in England.