For the past few years, companies around the world have been testing out a four-day work week. In many cases, this means allowing employees to spread their work hours over four days instead of five. Many of these tests have been successful, and people in the UK may soon get more rights to ask for a four-day work week. Since April, employees in the UK have had the right to ask for more flexible working conditions, but companies do not have to agree to it. But under the government's plans to increase flexibility for workers, companies may have to offer flexible working hours from the day the employee starts working — although it's not yet clear what this means. "One possibility is for the government to make it more difficult for employers to refuse such requests, because at present it is quite easy for them to do so," Charlie Thompson, an employment lawyer who works for law company Stewarts, told Sky News. Education Minister Jacqui Smith said more flexibility could be better for productivity. "You're still doing the same amount of work, but perhaps you're doing it in a way that enables you, for example, to need less child care, to spend more time with your family, to do other things, that encourages more people into the workplace," she told LBC Radio. But not everyone is happy with the idea of a four-day work week, and some tests weren't as successful as others. UK supermarket Asda tested a four-day week, but changed back to the five-day week after staff said the longer work days were too demanding. Another supermarket, Morrisons, also tried a four-day work week at its head office, but to make it work, staff sometimes had to work on Saturdays, which they weren't happy about.