"Curfew inspectors" were spotted patrolling central London on the first night of the government's new 10pm cut-off rule.
The marshals wandered around the bustling streets of Soho searching for "illegal speak easies" yesterday.
The City of Westminster employees were photographed looking through letterboxes and windows for any signs of activity.
They were seen outside some of London's most famous nightspots, including Ronnie Scott's Jazz Club and the Hippodrome Casino.
One person claimed central London was busier than she had seen it in months as revellers all "rolled out" onto the streets at the same time when the pubs closed.
One observer, Dan Barker, tweeted a picture of "curfew inspectors" patrolling Soho and looking into letterboxes.
He said: "Strange sight - City Inspectors, working through Soho, looking for illegal speakeasies open after the 10pm cutoff."
Twitter user Kirsty Lewis, 24, from north-west London, posted a video of the moment people exited pubs and restaurants on Oxford Street.
She tweeted: "10pm curfew just meant everyone rolling out onto the streets and onto the Tubes at the same time and it was the busiest I've seen central London in months."
Revellers out in Soho last night downplayed the dangers of coronavirus and said the country needed to "crack on".
Sophia Warne told the Guardian: "There’s mental issues, cancer, all this other stuff, yet everyone is paying attention to Covid. Look at how many people are actually in hospital because of it, it’s not actually very much. I think we need to crack on."
University student Colin Chen added: “How long are we going to wait for a cure for?
“Even if we wait till there’s no new cases, there’s just going to be cases again when people come in from overseas. This pointless curfew is punishing young people.”
Others said the curfew was "depressing" as they had to start their night "way earlier".
All pubs, bars and restaurants had to shut by 10pm last night to comply with new rules that were brought into force earlier this week.
But many people were not put off a midweek tipple or two by the new restrictions, with many pub-goers spotted in Soho.
A small police presence was seen on the pedestrianised streets but no problems were reported.
The Metropolitan Police said Commissioner Cressida Dick was out on patrol in Shoreditch, a popular nighttime area, with local officers "who were engaging with members of the public, to remind them of their responsibility to keep themselves and others safe to minimise the spread".
The force said it would be stepping up its enforcement of Covid regulations in response to the changes and rising rates of infection in the capital.
The rules for England contrast with those in Wales, where pub-goers will be given an extra 20 minutes to finish their drinks after last orders.
Changes to coronavirus regulations brought in at 6pm on Thursday mean Welsh hospitality businesses including pubs, cafes, restaurants, sports clubs and casinos must not supply alcohol between 10pm and 6am the following day.
Licensed premises are only able to provide table service for customers when consuming food or drink - and following a 20-minute period to allow customers to finish their drinks at 10pm - must close by 10.20pm.