Drinking Customs of the English

From Watching the English: The Hidden Rules of English Behaviour, by Kate Fox, p. 256ff.

Choosing a Drink

... your choice of drink (in public at least) is determined mainly by your sex and social class, with some age-related variations. The rules are as follows:

Round Buying Etiquette

There is usually no excuses for failing to perform the sacred round-buying ritual, but there are a few exceptions to the round-buying rules, relating to the size of the drinking group and the demographics of its members.

THE NUMBERS EXCEPTION In a very large group, traditional round-buying can sometimes be prohibitively expensive. This is not, however, usually seen as a valid reason to abandon the ritual altogether. Instead, the large group divides into smaller sub-groups (nobody suggests or organizes this, it just happens), each of which follows the normal round-buying procedure. ...

THE COUPLE EXCEPTION In some social groups, couples are treated as one person for the purposes of round-buying, in that only the male half of the couple is expected to "buy his round". ... In normal circumstances, you will only see this practice when the males in the group are over forty. ...

THE FEMALE EXCEPTION Women generally have considerably less reverence fo the round-buying rules than men. In mixed-sex groups, they play along, humouring their male companions by following the prescribed etiquette, but in all-female gatherings you see all sorts of odd variations and even outright flouting of the rules.

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