Companies are turning their backs on the concept of 'dress-down Fridays', opting instead to ditch smart business-wear every day of the week.
A survey of 560 organisations has found that four out of five employers believe a more relaxed dress code leads to greater productivity.
Nine out of 10 organisations that replied to the poll by the Peninsula employment law consultancy had declared ties an unnecessary part of their dress code.
Peter Done, managing director of Peninsula, said the popularity of 'dress-down days' and relaxed attitudes to dress codes have soared in recent years.
"The traditional standards of attire for work are ever-diminishing and this has become apparent during the recent heatwave," he said. "Traditional conventions within which business is conducted are being challenged and are constantly changing to meet the demands of the growing global environment."
The TUC has launched a 'Cool Work' campaign urging employers to let their staff wear fewer clothes in the present heatwave.
"Not only will a cool approach to work avoid staff wilting at their desks, it could also save companies money as they should be able to turn down the air con a notch," said TUC general secretary, Brendan Barber.