Time is the scarce commodity of the new world of work. Western economies are diagnosing citizens with "hurry sickness", families face a "time famine" and the lifespan of door-close buttons on lifts is shortening. Meanwhile, businesses are coming to terms with the rise of the 24-7 society, working across time zones, and concerns over work-life balance.
"Time is now a central social and economic issue," says Melanie Howard, from the London-based Future Foundation. "The distribution of time between different workers, between men and women, between households is changing rapidly."
And time has re-emerged as a potential battleground between firms and staff. Surveys across Europe show that employees report a higher level of work intensity, with more deadline pressure and, for many, longer working hours. In the UK one in four men is a "48-er", clearing the legal maximum 48-hour working-week mark. One in nine puts in more than 60 hours.
On the one hand, US "caffeine capitalism" is pushing up working hours. Americans have just overtaken the Japanese to put in the longest hours in the world. Silicon Valley has bred "sleep camels", who store up sleep on Saturdays and Sundays then work incessantly all week.
In Europe, the time war has been conducted at a legal level, with a 35-hour working week in France and the European Union's (much-ignored) directive limiting work time to 48 hours across the continent. There has been a cultural backlash too - in Italy, 33 towns have declared themselves "slow cities".
Yet research shows that the people who are enduring excessive hours are not the exploited working class. They are the newly affluent knowledge class. Among British employees working more than 60 hours a week, 70 per cent say they enjoy their job, compared with 57 per cent across the whole working population. The number of workers who say their job is "just a means of earning a living" varies dramatically by hours worked, from 42 per cent among those working 35-39 hours a week to 22 per cent among those working more than 60 hours a week.
The extra hours are largely unpaid and are being put in by women just as much as men, according to Susan Harkness, an economics lecturer at the University of Brighton. One in three women with children now works for more than 40 hours a week, she calculates - up from fewer than one in five just 10 years ago.
In addition, the proportion of working mothers putting in free overtime has soared from 18 per cent to 47 per cent. According to Harkness: "Hours worked beyond the contracted time, and mostly unpaid, are the real reason for the increase in working hours. It is professionals who are adding the unpaid hours on, especially professional women, who are catching up with the men."
At the same time, the clear distinction between work and life is breaking down, making traditional approaches to the work-life balance less likely to stick. In the industrial era it was clear when someone was working and when he or she was not - and firms needed their staff at their posts. So the notion of a fixed workday, work week or work year is a specifically industrial idea. It makes sense for factories - plants need production-line workers to be at their posts at predictable times.
In the industrial era, it was broadly correct to say that time was money. Today, thought is money. And thoughts are like buses; you can have three in a row, then none for hours. Albert Einstein produced three of the last century's most significant scientific papers in one year, 1905, but nothing really worthwhile for the last 30 years of his life. You can't pay knowledge workers by the hour - they can have their best, most value-adding thoughts in the bath on a Sunday, and do little more than shuffle paper all day Monday.
Even in France, the lines between work and home are blurring and employees are using their time more flexibly. According to Jean Viard, director for political science research at the Paris-based Centre for the Study of French Life: "Today some work nights, others work on a Sunday. And employees are using the freedom resulting from the 35-hour week not to be in the same place as everybody else at the same time.". Once business virtually closed down in the summer. But now three out of 10 French people go on holiday outside the traditional months of July and August. "Who now would talk of 'grandes vacances'?" asks Stephene Jourdian in L'Expansion magazine.
What employees say they want is not necessarily fewer hours, but more control over their time. Only one in five British workers say they would opt for a fixed nine-to-five shift; half want to work flexibly between 7.30 a.m. and 7.30 p.m. The remainder want to be able to work whenever they choose. Smart companies are rethinking the notion of working time and are liberating staff from the drudgery of the nine-to-five. They are judging them purely by task, not time; they are endowing their workers with time sovereignty. London-based Ideas Unlimited, a thriving management consultancy, is one such firm.
Founder Sue Maguire says: "I wanted to create an environment for people where there is no start and finish time. There are no restrictions on holidays. If you want to take a day off work, or two weeks, take it. Let's be adult people. We have a lot of freedom here but also a lot of responsibility."
One of her employees, Karen Lynn, explains the rhythm of work at Ideas Unlimited: "We work very long hours in periods, and then we have long periods off."
Maguire recognises that different people work better at different times of the day and under changing circumstances. It is a biological fact that some people are ferociously productive early in the morning, while others are barely civil until noon and then come alive in the early evening.
We can all see these different types in our homes and our offices. There are some people you know not to talk to until after 11 a.m. and their second cup of coffee; others are best avoided between 3 p.m. and 4 p.m, when they should probably be taking a nap. Rather than trying to force individual biological clocks into an artificial workday, time sovereignty is about letting people work when they will be most productive.
Time sovereignty poses at least three challenges for firms. How can they know if staff are actually working? What about clients who expect their account handlers to be available during "normal" working hours? And how can you ever build successful teams if people are coming and going as they please?
Some staff clearly have to be at their posts between hours A and B. But the accountant in the car factory does not have to work from 8.30 a.m. to 4.30 p.m. just because the people on the shop floor do. Nor does the marketing manager of the coffee shop chain need to work 9 a.m. to 5 p.m. because that's when the cappuccino is served.
Staff who are engaged in computer -based work are hard to monitor successfully anyway. Someone sitting at his desk could just as easily be e-mailing friends as working on quarterly sale forecasts. Instead, managers need to learn to judge people by what they produce, not when they produce it. New research commissioned by the Industrial Society shows people who are working flexibly actually work harder than those who do the nine-to-five - perhaps because they know they will be judged by results alone.
As Marcia Bromit Knopf, a US sociologist, says: "Flexible work arrangements are a kind of 'letting go' model. It's saying: here's our vision; at the end of the process we want to achieve the following goal. That way, you aren't judged if you are there from Monday to Friday or from seven to seven. You are judged by what you produce."
This means significant changes in management styles and skills. It is comparatively easy to manage people to be physically present in a particular place between certain fixed hours - rather like taking the register in a primary school class. Managers schooled in industrial time can find time sovereignty difficult.
They walk into an empty office and ask: "Where is everybody?" But if managers cannot drop the industrial mindset, it probably means they are past their sell-by date anyway. Time management is poor management.
The second legitimate concern is client contact. One senior investment banker says: "We have clients ringing with a cold sweat at 3 a.m. and we have to talk to them." And plenty of clients want access to the right people between nine and five. This is where communication technology developments are so powerful. Just because some staff are spending the morning out of the office does not mean they can't take their mobile phone or laptop and get back promptly to queries.
Time sovereignty recognises - even celebrates - the messiness of modern work and life. Some firms now use "response times" as part of the employment contract rather than "working times" - so, for example, regardless of where staff are or what they are doing, they should return calls within the hour.
Finally, there are concerns that time-sovereign teams will be unable to connect. It is necessary for there to be certain meeting times or working times when team members can share information and ideas. But they do not have to be together all the time to achieve this - how many football teams need to be together eight or 10 hours every day in order to play as a team on Saturday? In fact, working very long hours a few yards away from the same person every day can be counter-productive in terms of team spirit.
Smart firms are giving up the fight to control the time of their workers. They have realised that buying a person's physical presence does not buy the best their brain can offer. They are throwing off the shackles of the nine-to-five and embracing a freer notion of work and a blurred line between work and life. It could be that they are showing the way to an altogether different way of working.
Richard Reeves is director of futures at the Industrial Society and author of Happy Mondays - Putting The Pleasure Back Into Work, to be published by Pearson in May