Employers should ensure their workers take their full holiday allocation or risk stress-related illness among their workforces, according to Bupa.

A YouGov study commissioned by the organisation found that 42 per cent of employees are not planning a holiday of a week or more this year, with 56 per cent saying they can't afford to.

This is despite more than half (52 per cent) of Brits saying they are more stressed than ever before and 47 per cent saying they have seen a noticeable improvement in their mental wellbeing after taking a break.

BUPA's clinical director of occupational health, Dr Jenny Leeser, said not taking the time to switch off could be having a detrimental impact on health.

"If financial restraints mean that a week long holiday is unlikely this year, it is still important that employees feel encouraged to take time off from work to rest, even if they stay at home," she said.

"When taking a break, employees should be encouraged to switch off from the workplace to ensure that they return refreshed and better equipped to deal with everyday pressures."

According to the Health and Safety Executive, in 2009/10 an estimated 9.8 million working days were lost through work-related stress.