At six o’clock each morning, before the kettle has spoken, your stylist has already read the day. It has consulted your calendar and noted Thursday’s board dinner; it has taken the measure of the weather over Mayfair; it knows the gallery opening has moved, and that rain is expected by four.

It remembers, too, what you would rather it only whispered: the silhouette that flatters you most, the colours you reach for and those you merely admire, and every look you have worn these past ninety days — so that nothing returns before its time.

From all of this it composes a single recommendation: one look, drawn from the network’s open wardrobes, reserved with a word. Decline it, and a second reading arrives within the minute. The stylist does not sulk.

It is tireless in the way only very good staff once were. It does not sleep, does not take August off, and repeats none of your confidences.

The question first appeared on a placard outside a London show, held aloft by a woman in borrowed couture who declined to name the house that had shared it. By Paris it was a chorus; by Milan, a movement; by New York the four syllables had acquired their own hashtag and a following the industry could no longer politely ignore.

Buy or borrow? The mob — if so elegant a gathering can bear the word — asks nothing else. They arrive at the tents impeccably dressed, entirely in borrowed pieces, and let the question do its quiet work. Photographers, unable to tell them from the front row, have stopped trying.

The campaign claims no leader and issues no manifesto beyond the placard itself. Its members will say only that the finest garments they have ever worn were never theirs, and that this discovery ruined ownership for them entirely.

Asked what becomes of the clothes after each appearance, one participant smiled. “They go on to someone else. That is rather the point.”