Employers are increasingly dictating to staff what they can and cannot wear in the workplace - but the decline of the business suit has left workers unsure about standards of dress.
A study of 66 companies by the journal IRS Employment Review found that, while standards of dress are becoming less formal, the policing of what is and is not acceptable for the office is being tightened up.
More than two-thirds – 67 per cent - of dress code policies now had the force of the employment contract behind them.
This was 15 per cent up on the previous IRS survey in 2003, showing that fewer employers are now content to keep their guidelines informal.
Fewer than a third – 31 per cent - of employers with formal dress code policies granted dispensations on religious grounds.
This was despite the fact that such inflexibility could now leave them open to claims of discrimination on the grounds of religion or belief.
Dress codes were mostly used for company branding, image and culture reasons, with health and safety, practicality and hygiene also considered practical reasons for having a code.
Where organisations did not have a dress code it was normally because there was a general belief that employees could be trusted to wear appropriate clothing.
More than six out of ten did relax their dress codes from time to time, for instance for dress-down days.
IRS Employment Review managing editor Mark Crail said: "Employers believe dress codes must be relevant to business needs, to individuals and to organisational culture. With increasing emphasis on corporate image, it is not surprising that many employers regard workplace attire as a serious business."
It was still unclear how far the legislation outlawing discrimination on the grounds of sexual orientation and religion or belief would affect workplace dress policies, he cautioned.
"Some employers are already reviewing their dress codes to ensure that they do not inadvertently lead to direct or indirect discrimination on these grounds,” he added.
