Seven million people in the UK are now economically active at night.
Is it a question of profits over health?
That number is set to double in the next decade.
But experts are warning that working round the clock is also putting our health at risk.
The traditional 9-to-5 is becoming a thing of the past.
We now work longer hours than any other country in Europe - weekends, evenings and nights. 24-hour Britain has arrived.
But health experts warn that people who regularly change their sleep patterns may be at a higher risk of developing heart disease, diabetes and other metabolic disorders.
Julie Ann Greenslade works alternating day and night shifts as a CCTV operator for Tamworth Borough Council.
Whilst she's proud that her team's work has resulted in over 500 arrests in the last year, the job has taken a toll on her body.
"If I only manage to have eight hours over two days, by the third night I am physically feeling sick," she says.
"I get to a certain time when my body temperature falls, then I start feeling nauseous, I get a stinking headache and I need to go and be sick."
Working irregular hours enable many to look after their children
As Ms Greenslade's sleep patterns get turned on their head, so do her meal-times - which causes its own problems.
She has gained two stone in weight since she started working nights.
"Because your body should be shut down and asleep, you don't burn off what you're eating. It just lies there and that's when you tend to put weight on," she says.
"Half-way through your shift, you become hungry and the only places that are open are fast-food restaurants, or you bring microwave meals in, so it's all junk food."
Professor Jo Arendt at Surrey University has studied the health effects of shift working.
She is concerned by the current trend.
"Split shifts are the worst for us," she says.
"People choose them because they fit most conveniently into their lives."
Increasingly, however, shift-workers are prepared to sacrifice both a good night's sleep, and often their health, for the benefits flexible working offers.
Melanie Howard, co-founder of the think-tank the Future Foundation, has written several reports looking at the UK's burgeoning 24-hour economy.
She argues that this flexibility is particularly appealing to working women.
"Nowadays the majority of women will stay at work even after childbirth, which has caused a sort of time-famine in terms of getting in the shopping," she says.
"The other thing that's happening is those same women who want to stay in work are able to take on shift-working jobs that are the lifeblood of the 24-hour society. They're creating a demand and satisfying a demand at the same time."
Sharon Dyer balances a job working nights at First Direct's call-centre in Leeds with raising her ten year old son, Sam.
"It just means that I'm there to pick him up from school every day. And of course school holidays. I'm in the house with him. If he needs me, I'm there."
Getting rich overnight
Sharon and her colleagues - affectionately known among day shift workers as 'The Mushroom Squad' - are certainly kept busy.
First Direct, one of the first to offer a round-the-clock telephone banking service, estimates that 40% of their calls are taken outside of regular office hours.
The bank's phone-lines have been continuously open to calls since October 1989 and it now boasts over a million customers, many of whom would struggle to get to a high-street branch during the working day.
With services like telephone banking now available around the clock, consumers are becoming more demanding elsewhere too.
Britain's largest bed manufacturer, Silentnight, introduced a night shift five years ago in order to keep up with demand and to cut down the time customers have to wait before their product gets delivered.
"We want things now, now, now," says Ian Fortune, who manages the team of 125 night-workers at the company's factory in Barnoldswick, Lancashire.
"Since we've had the night shift on, our productivity has gone up, but also the customer sales that we've been bringing in have gone up by 18%."
A Crackberry addiction
Advances in technology mean that you don't even have to be in the office to be at work these days.
Nightworkers enable shoppers to get what they want when they want it
City lawyer Andrew Young carries a Blackberry with him wherever he goes, which means he can use time otherwise wasted in the back of taxis and waiting for flights answering emails from clients around the world.
"It's democratised the way we work," Mr Young says.
"The nine-to-five culture is dead and buried. People don't work nine-to-five anymore, they work as long as they have to work.
"And if it's their business, they're always on. If they're awake and it's feasible to work, they will be working."
But while the Blackberry is good news for business, it carries its own costs for the families of those becoming addicted to the hand-held devices.
A new breed of so-called 'Crackberries' has emerged.
"It does cross the boundary of family life and work life," says Mr Young's wife, Gigi.
"There are no more boundaries. He's at work all the time."
It is estimated that as many as 13 million of us will be economically active by 2020, either as shift workers or as increasingly voracious consumers of the 24-hour economy.
But, with health experts warning that only 10-20% of us can ever successfully adapt to night work, the booming night-time economy will not be without its cost for those of us prepared to embrace it.
"There's a 40% increase of heart disease in night shift workers", explains Professor Arendt.
"And recently about the same increased risk of having breast cancer if you're a nurse according to an American study."
Twenty-four hour Britain may be good for business. But night workers will pay the price.
The Money Programme: Bye Bye Nine to Five. BBC Two at 7pm on Friday 24 March.