“ It was the language of the officials which really fascinated me. It was in effect a private code, which seemed to have arisen as a means of expressing strong disagreement between gentlemen without lapsing into incivility, so certain words which might appear anodyne became charged with sharper meaning. A good example would be “unhelpful”. This expressed dissatisfaction, irritation, even real anger, in the guise of a sort of rueful acceptance.”
Source: joemoransblog.blogspot.com