London businesses are already counting the cost of work-from-home rules as employees shun the city centre in a bid to control the spread of the Omicron coronavirus variant.
Pictures from the City of London showed some streets were left near-deserted as the guidance on office working came into effect in the early hours of the morning.
Coffee shops, restaurants and other small retailers that would normally be thriving during the busy Christmas period may now struggle to stay afloat because to the reduced customer presence, commerce leaders have warned.
Catherine McGuinness, Policy Chair at the City of London Corporation, said the Plan B restrictions were a "blow to businesses" operating in the square mile.
Speaking on Monday, Ms McGuinness warned that many small enterprises may struggle to survive if further government support is not forthcoming.
"Clearly health has to come first and everyone has to follow the rules and the guidance. But first of all we need to weigh and balance the impact on the economy."
Financial services had adapted well to the work from home guidance, she said. However, she warned that 'street level' businesses which have lost customers ahead of Christmas may struggle going forward.
"It's another massive challenge during the end of a very challenging year. I'm very concerned for them."
She added it was "not sensible" that employees were allowed to attend Christmas parties but were asked to stay away from socially distanced offices, to which she urged a return to "as soon as possible".
Commuters said their journeys into work were quieter than usual as data showed a significant drop in traffic on the capital's roads on Monday.
A Twitter user in the capital wrote: “Everywhere is extremely quiet again. Have school holidays started? Or is everyone working from home? No one at the bus stop. No traffic. No people walking. Very weird for a Monday.”
Several people travelling by train to London reported that services were quieter on Monday morning. A photograph of a near-empty escalator of Waterloo station was posted on Twitter by @lucitelu, with the caption: “Stations are quiet again. This is Waterloo, 9:15”.
Figures from location technology company TomTom show cities across England experienced a decline in traffic on Monday morning.
In London at 8am, congestion levels were down from 72 per cent two weeks ago to 60 per cent.
Transport for London said demand for Tube services as of 10am on Monday was about 18 per cent lower than it was last week, while bus usage was down about 5 per cent.
Overall Tube use up to 10am was at 46 per cent of pre-coronavirus levels, with demand for buses at 71 per cent.
Coronavirus in the UK - in pictures
A TfL spokesman said the drop in overall ridership levels would badly hit its operating income, which relies heavily on fares revenue.
Last week, research revealed that Britain's city centres could lose £3 billion ($4bn) in 2022 alone as more people stay away from their workplaces and spend money in their local area instead.
The University of Sheffield study found that employees will be working about one day a week more at home than they were before the pandemic, with the shift in working habits expected to be permanent.
London is expected to be worst hit, with the City financial district expected to suffer a 31 per cent drop in spending, followed by central Birmingham, which could experience an 8 per cent decline.
Prime Minister Boris Johnson urged people in England to work from home where possible from Monday as he outlined a series of new Covid restrictions last week.
Other measures included the introduction of vaccine passports and mandatory wearing of face masks at shops and other indoor venues.
It comes as the UK Covid alert level was raised to Level 4 from Level 3 after a rapid increase in the number of Omicron cases.
As of Sunday, the UK had recorded another 1,239 cases of the strain, bringing the total to 3,137, a 65 per cent increase week on week, amid some warnings that the true level was 10 times as high.