Britain is dividing into a two-tier workforce as office staff benefit from flexible working but the conditions of frontline staff such as nurses and shop workers remain “frozen in time”, according to a report.

Workers who were considered to be on the frontline during the pandemic have seen no change to their working hours or shift patterns in recent years, according to research by Timewise, a social enterprise that helps businesses with flexible working policies. This is despite the post-pandemic rise in hybrid working for office-based staff.

As a result, the world of work remains “frozen in time” for people in sectors such as retail, transport, health and social care and construction, it found, even though they account for about a third of the UK workforce, representing 10.5 million people. Many of these roles involve shift work and are based at a set location, while some are on zero-hours contracts.

“For millions of site-based and shift-based workers in particular, it is impossible to meet essential needs like being able to take time out for a medical appointment, to plan ahead or to manage working hours around a health condition,” said Clare McNeil, a director at Timewise.

“This is creating a two-tier workforce between office-based employees who are increasingly better able to manage the demands of work and life, and the frontline workers who keep our country moving,” she added.

Between 2019 and 2024, more than 1.3 million people in desk-based roles gained access to flexible hours, representing 14% of all office-based workers, according to official figures from the Office for National Statistics (ONS). However, there was no change in the 6% of the UK’s 3.4 million shift workers who said they were able to vary their working hours, representing just 250,000 people.

Timewise is calling on the government to take action to ensure that lowest-paid workers also benefit from the changes in the employment rights bill – designed to make sweeping changes to rights at work – which is making its way through parliament.

Increasing flexibility for shift-based workers could help companies to retain more staff or recruit new employees more easily, the report found, and could also aid the government in its goal of reducing “economic inactivity”, or managing labour shortages.

The year-long programme of research conducted by Timewise with workers, employers, unions and sector leaders found that businesses, particularly in sectors which rely on shift work, require help with “the workplace culture, business and operational shifts needed” to introduce flexible working.

Companies often blame operational challenges and the costs of implementing new shift patterns as the reason for failing to introduce flexible working, the report found.

“It is complex in terms of scheduling, in terms of rostering, and there are a number of other barriers we identified,” McNeil said.

“We have carried out a pilot showing that you can make common sense changes that can really change people’s lives on a day-to-day basis, so they can get time off for their medical appointment, or get the flexibility they need for childcare.”

All UK employees currently have the right to request flexible working, yet many of the workers surveyed said they were not aware of this, while employers can refuse the request as long as they have a “good business reason” for doing so.

Construction is one of the sectors where there has traditionally been little flexible working and many roles are based on building sites.

Property developer BAM, which employs 6,700 people in the UK, first piloted flexible working schemes in 2019, and has since expanded them.

“We see this as an ability to bring the industry into the 21st century,” said Kim Sides, executive director for construction at BAM UK. “If you have to be physically on site, it doesn’t mean that flexibility can’t be dealt with in some other way, whether that’s different starting hours, different completing hours.”

The construction company, which built the new Victoria and Albert (V&A) museum in Dundee and the Coop Live arena in Manchester, believes that offering flexible working may help to attract younger workers to the industry.

“We’ve got an age profile in the construction industry that we’re aware of, and the pool is not refreshing itself like it used to,” said Sides.

The report comes as work-life balance outranked pay as a top motivator for the first time in an international survey of thousands of workers, underscoring the permanent changes brought to the world of work after the pandemic.