Speaking in the Commons on Thursday morning, the health secretary said the infection rate in the capital was on “a steep upward path”.
“We must act now to prevent the need for tougher measures later on,” he said.
Hancock told MPs: “Things will get worse before they get better but I know there are brighter skies and calmer seas ahead.”
London will move to tier 2, meaning from the weekend households will be banned from mixing indoors – including in pubs.
Essex, Elmbridge, Barrow in Furness, York, North East Derbyshire, Chesterfield and Erewash will also move to the same “high” alert level.
But a political row has meant no decision has been made on moving Greater Manchester into tier 3, the highest alert level, which would see pubs and bars not serving food forced to close.
A call between Greater Manchester leaders and Downing Street officials failed to reach an agreement on new restrictions and there will be further meetings later today.
Lancashire MPs have been told that the region will stay under tier 2 restrictions, despite speculation it would move into tier 3.
Defending the government’s decision to shun a national lockdown in England, Hancock told MPs “local action is at the centre of our response”.
“The virus is not spread evenly. The situation is particularly severe in some parts of the country,” he said. “We know we can control the virus because we have done it before.
“We must act now. Delayed actions means more deaths from Covid. It means more non-Covid deaths. And it means more economic pain later.”
Jonathan Ashworth, the shadow health secretary, repeated Labour’s calls for a two to three week national “circuit-breaker” in England.
“A full national lockdown stretching for weeks and weeks and weeks, like we had through April, May and June, would be disastrous for society,” he said.
“But we are urging him to adopt a short, time-limited two to three week circuit-break to take back control of the virus, to reboot and fix Test and Trace, to protect the NHS, to save lives.”
The new tiered system only came into effect on Wednesday and the decision to re-categorise areas so soon is an indication of growing concerns about the speed at which the virus is again spreading.