According to a US dress-down survey, the number of American companies with dress-down policies fell in 2000 for the first time since 1992.
There is evidence that the same is happening in the UK. At fund manager Britannic Asset Management, a majority of staff voted for a smarter look in an internal survey last November. Just 64 voted in favour of casual dress, and 114 voted against.
A spokesperson for the investment house says: 'It was felt that because a large number of clients and pension fund trustees are constantly in and out of the building, it was important to maintain a professional image.'
Gill Hicks, a senior consultant at Meridian Consulting, an outplacement specialist, is even more emphatic: 'An inconsistent level of authority and professionalism in our workwear will suggest that we are inconsistent in our moods and attitude.'
Fears about job security are also affecting dress.
An analyst at JP Morgan Fleming says: 'People in the City are nervous at the moment. They tend to dress smartly at work, almost as if they are going to interviews on a daily basis, because they do not know where they stand.'
Simon Virgo, business manager of online markets at Dresdner Kleinwort Wasserstein, says that many people were never very keen on dressing down in any case: 'Some take the increased choice, enjoy it for a short period of time and then revert to business suits.'
When dress-down policies were introduced, many people were unsure of what to wear, in case they projected the wrong image. But with a business suit, they felt they could not go wrong. More casual dress codes posed a dilemma, especially for those with limited fashion sense and who were used to the 'security blanket' offered by a formal jacket.
For those who do dress down, there is no shortage of advice. For men, Gareth Scourfield, fashion editor of Esquire magazine, recommends pinstripe trousers worn with a plain casual jacket, or a really smart suit with roll-neck knitwear.
Alternatively, a jacket with an open-necked shirt and cord trousers, or light cotton narrow chino trousers will do just as well.
He says: 'The City boys tend to go for Paul Smith and Hugo Boss and I would advise them to stick to that. Don't, for example, go shopping at Gap to achieve that casual look, because it could go too far.'
Olivia Davidson, a London-based fashion consultant, says that her male and female clients are opting for a sharper image. The women want to look feminine without being provocative and the men want to look smart.
Davidson, whose clients include bankers, corporate executives and lawyers, says: 'I provide advice depending on their job, the colours they favour, the clothes shops they go to, their age and size. I consider all this before revamping their wardrobe.'
One of her clients is Peter Trowell, managing director of City recruiter CityJobs.com. He says: 'There is still a very good Monday to Thursday routine of being fairly formal. The Friday dress-down code still has certain guidelines for key people. They might dress down to blazers and trousers, but that is about the extent to which they will go.'
Hicks at Meridian agrees that in the US there is a trend now towards 'dress-up Fridays', because people feel that they have less authority in casual attire and some find that their staff tend to be a bit more sloppy. Today's consensus seems to be to dress for the job you want rather than the job you have.
But a senior manager based at an American investment bank in London disagrees. 'Dress down is now here to stay and I have even had situations where clients have contacted us prior to a meeting and asked us to not come formally dressed.'
Hicks concludes: 'There is still some way to go before companies seek clearer guidelines on dress codes. Staff are expected to invent it themselves and, not surprisingly, mistakes are being made.'