When the right to request flexible working was extended to all employees in 2014, the move was heralded as a game changer in the workplace.

Image copyright Jodi Redhouse Image caption Georgie Gayler says she would never want to get a colleague in trouble but when people with kids take time off "it adds up"

With anyone eligible to ask to work from home and/or reduce their hours, it seemed that a narrative long synonymous with working mothers and childcare had finally broadened in scope.

Yet it appears we are some way off the level playing field anticipated. While technology continues to blur the boundary between home and the office and the rise of the gig economy demands more workplace agility, it seems childless employees are still experiencing a bias that makes a work-life balance a pipedream.

"From accommodating religious commitments to managing long-term medical conditions such as anxiety and depression, there are many reasons why people need to work flexibly, but many employers still view this as a privilege just for parents with young children," says Kate Headley, director of consulting at The Clear Company, which helps organisations recruit staff from a more diverse base.

"Instead, they need to open up their thinking to adopt flexible working and attract a whole new talent pool of qualified people that either can't or choose not to work traditional hours."

And for freelance social media director Georgie Gayler, who doesn't have children, a bias over formal flexible working requests is only part of the story.

In her experience inconsistencies are rife and unquestioned across a number of informal arrangements, from time off automatically given when children are ill to leaving work early or coming in late to accommodate their needs.

"If their children are sick, or they need flexible working suddenly due to difficulties at home, then of course this should be recognised, but at the same time, the job still needs to be done and without an impact on other colleagues, and this is where it can often fall," she says.

"I'd never want to get a colleague in trouble over what might be considered a 'petty' 30 minutes here and there, but it adds up and is noticed more than managers and HR departments think."

Image copyright Thinkstock Image caption Parents leaving work early or coming in late because of the school run can cause tension with co-workers

With tensions particularly acute when it comes to "picking up the slack", some employment lawyers think there could be scope for a change in the law to ensure like-for-like hours.

Such a development would be welcomed by people like marketing professional Ryan Lock. The 30-year-old jumped ship from his most recent job, having found that the flexible working culture promoted as an organisation-wide benefit was a perk available only to parents.

"I've seen colleagues have to fight really hard for something that has been advertised to them while having to cover when working parents take leave at short notice," he says.

"For me, flexible working is something that empowers you to work where and when you feel you can be most productive, be it home, the office or a coffee shop, whereas I do think a certain generation of senior management with children see it as a chance to block out windows for extracurricular activities."

Image copyright Thinkstock Image caption For many millennials, flexible working means being able to work in environments where you can be the most productive

As a millennial, he's part of the demographic increasingly rejecting the nine-to-five working model and demanding more from their employers. It's a group that Claire Knowles, a partner at Acuity Legal, believes will be the driving force behind future legislative change in the next five years.

In the meantime, while complaints against employers for unfair treatment are common, she admits few make it to tribunal. Perhaps even more surprising is the negligible rise in requests from childless employees to work flexibly since the legislation changed.

"The most common grievances around flexible working generally still involve parents - usually women - who have requested flexible working for an average of three years while they start families, but they then expect to be able to revert back to their normal working hours immediately and employers can't accommodate this," says Ms Knowles.

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While some cite a simple lack of awareness, Sir Cary Cooper, psychology professor at Manchester Business School, argues that internal pressures and a precarious economic climate are deterring childless employees from "rocking the boat".

As lead scientist on The Foresight Project: Mental Capital and Wellbeing he was tasked with advising the government on how to achieve the best possible mental well-being in the population, a study which included an in-depth look at the workplace.

Image copyright Thinkstock Image caption Women who request flexible working to start families are often surprised when they cannot later return to their original working hours

His recommendation to extend the right to request flexible working was a catalyst in the law being changed, but now he would like to see childless employees pursue the right more robustly.

"There is concern particularly with men that requesting this shows a lack of commitment but we now have this law, a bedrock that says it's ok [to ask] and that employers have to give a very good reason for not granting it," he says.

"From a talent management perspective and given the technology we now have at our disposal I don't understand why all employers aren't embracing it, given the impact flexible working has on productivity."

Indeed, his report found that the benefit to the UK economy associated with offering the right to request flexible working to parents with children to be around £165m, and when opened to non-parents of working age the figure rises to £250m.

Image copyright Lloyds Image caption Non-parent Claire Hyde is grateful that her employer lets her jobshare

Lloyds Banking Group was an early proponent of opening flexible working to all. The company says putting bottom line before presenteeism has increased productivity, including a 10% rise in answered calls as well as increased employee satisfaction and retention rates.

The company's joint head of internal communications, Claire Hyde, who doesn't have children, is a case in point. With 15 years' service to date, her three-day-a-week jobshare arrangement includes a mix of office and home working.

"I really appreciate being with a company that doesn't discriminate based on parental status. Everyone's individual circumstances are different and people may have other caring responsibilities, roles in their local community or additional personal commitments, organisations should be recognising and adapting to this."

And with 19 million people without dependents employed in the UK and global childlessness on the rise, perhaps she has a point.