Dear Mary | 7 July 2012

Q. An old friend invited me to have dinner with him in London. We had just sat down when a couple he knew walked into the restaurant. They were slightly drunk and noisy and very excited to see him and made quite a fuss around our table so other diners started to look over. My friend felt he had no option but to suggest the waiter pull up another table and the couple sit down and join us. Afterwards we both felt sorry we had not been able to chat to each other. How, without seeming unfriendly, could he have tactfully encouraged them to move on?
— A.B., Great Dunmow

A. Etiquette would have decreed that your friend stand up to greet the couple. Did he? Like all courtesies, this one has a practical purpose: it signals respect while discouraging lingering. Meanwhile the way to pre-empt a full scale intrusion of the type you suffered would have been for your friend to ask eagerly at the outset, ‘Will you join us for coffee?’