Guidelines for business dress
Generally, dress is moderately but not rigidly formal.
It is common, even in fairly formal organizations (except, say, banking and the law), and at a senior level, for men to wear sports jacket/pants and tie. However, there are subtleties about the “right” kind of jacket, shirt and tie which are too complicated to bother about, so I still always go for the standard suit.
Long sleeved shirts/blouses are important, especially for men. Only foreign men wear short sleeved shirts with a tie, apparently.
Women (and often men, for that matter), are clothes brand conscious and will usually dress “well” but not necessarily power dress. Again, go for conservative = safe. Conservative can include pants/(UK =”trousers”) for women if as part of a suit or “chic” outfit.
Casual dress (i.e. no tie for men and however you define the equivalent for women), is still not widespread in business at management level, even in many hi-tech/software etc industries, although there are exceptions and some companies with dress down Fridays.
It is fine to take off your jacket in a meeting if you are hot (“Do you mind if I…”, is a good idea) but don’t roll up your sleeves unless they do.
Socially, follow the normal rules except that people are dress conscious and so clothes (even jeans and T-shirt) should always be coordinated and clean. “Scruffy” is not a part of normal, over-21 dress vocabulary in public. Particular points: if invited to a meal and you don’t know the dress code, men should wear a tie – you can always take it off; theatre (ballet, opera, classical music concerts), are moderately formal and so a tie is safe but dinner jacket/black tie (US= “tuxedo”) and equivalents for women are rarely worn.